Thursday, August 30, 2007

SQL Server Interview Questions

What is RDBMS?
Relational Data Base Management Systems (RDBMS) are database management systems that maintain data records and indices in tables. Relationships may be created and maintained across and among the data and tables. In a relational database, relationships between data items are expressed by means of tables. Interdependencies among these tables are expressed by data values rather than by pointers. This allows a high degree of data independence. An RDBMS has the capability to recombine the data items from different files, providing powerful tools for data usage.

What is normalization?



Database normalization is a data design and organization process applied to data structures based on rules that help build relational databases. In relational database design, the process of organizing data to minimize redundancy. Normalization usually involves dividing a database into two or more tables and defining relationships between the tables. The objective is to isolate data so that additions, deletions, and modifications of a field can be made in just one table and then propagated through the rest of the database via the defined relationships.

What are different normalization forms?

1NF: Eliminate Repeating Groups
Make a separate table for each set of related attributes, and give each table a primary key. Each field contains at most one value from its attribute domain.
2NF: Eliminate Redundant Data
If an attribute depends on only part of a multi-valued key, remove it to a separate table.
3NF: Eliminate Columns Not Dependent On Key
If attributes do not contribute to a description of the key, remove them to a separate table.
All attributes must be directly dependent on the primary key
BCNF: Boyce-Codd Normal Form
If there are non-trivial dependencies between candidate key attributes, separate them out into distinct tables.
4NF: Isolate Independent Multiple Relationships
No table may contain two or more 1:n or n:m relationships that are not directly related.
5NF: Isolate Semantically Related Multiple Relationships
There may be practical constrains on information that justify separating logically related many-to-many relationships.
ONF: Optimal Normal Form
A model limited to only simple (elemental) facts, as expressed in Object Role Model notation.
DKNF: Domain-Key Normal Form
A model free from all modification anomalies.

Remember, these normalization guidelines are cumulative. For a database to be in 3NF, it must first fulfill all the criteria of a 2NF and 1NF database.

What is Stored Procedure?
A stored procedure is a named group of SQL statements that have been previously created and stored in the server database. Stored procedures accept input parameters so that a single procedure can be used over the network by several clients using different input data. And when the procedure is modified, all clients automatically get the new version. Stored procedures reduce network traffic and improve performance. Stored procedures can be used to help ensure the integrity of the database.
e.g. sp_helpdb, sp_renamedb, sp_depends etc.

What is Trigger?
A trigger is a SQL procedure that initiates an action when an event (INSERT, DELETE or UPDATE) occurs. Triggers are stored in and managed by the DBMS.Triggers are used to maintain the referential integrity of data by changing the data in a systematic fashion. A trigger cannot be called or executed; the DBMS automatically fires the trigger as a result of a data modification to the associated table. Triggers can be viewed as similar to stored procedures in that both consist of procedural logic that is stored at the database level. Stored procedures, however, are not event-drive and are not attached to a specific table as triggers are. Stored procedures are explicitly executed by invoking a CALL to the procedure while triggers are implicitly executed. In addition, triggers can also execute stored procedures.
Nested Trigger: A trigger can also contain INSERT, UPDATE and DELETE logic within itself, so when the trigger is fired because of data modification it can also cause another data modification, thereby firing another trigger. A trigger that contains data modification logic within itself is called a nested trigger.

What is View?
A simple view can be thought of as a subset of a table. It can be used for retrieving data, as well as updating or deleting rows. Rows updated or deleted in the view are updated or deleted in the table the view was created with. It should also be noted that as data in the original table changes, so does data in the view, as views are the way to look at part of the original table. The results of using a view are not permanently stored in the database. The data accessed through a view is actually constructed using standard T-SQL select command and can come from one to many different base tables or even other views.

What is Index?
An index is a physical structure containing pointers to the data. Indices are created in an existing table to locate rows more quickly and efficiently. It is possible to create an index on one or more columns of a table, and each index is given a name. The users cannot see the indexes, they are just used to speed up queries. Effective indexes are one of the best ways to improve performance in a database application. A table scan happens when there is no index available to help a query. In a table scan SQL Server examines every row in the table to satisfy the query results. Table scans are sometimes unavoidable, but on large tables, scans have a terrific impact on performance.

Clustered indexes define the physical sorting of a database table’s rows in the storage media. For this reason, each database table may have only one clustered index.
Non-clustered indexes are created outside of the database table and contain a sorted list of references to the table itself.

What is the difference between clustered and a non-clustered index?
A clustered index is a special type of index that reorders the way records in the table are physically stored. Therefore table can have only one clustered index. The leaf nodes of a clustered index contain the data pages.

A nonclustered index is a special type of index in which the logical order of the index does not match the physical stored order of the rows on disk. The leaf node of a nonclustered index does not consist of the data pages. Instead, the leaf nodes contain index rows.

What are the different index configurations a table can have?
A table can have one of the following index configurations:

No indexes
A clustered index
A clustered index and many nonclustered indexes
A nonclustered index
Many nonclustered indexes

What is cursors?
Cursor is a database object used by applications to manipulate data in a set on a row-by-row basis, instead of the typical SQL commands that operate on all the rows in the set at one time.

In order to work with a cursor we need to perform some steps in the following order:

Declare cursor
Open cursor
Fetch row from the cursor
Process fetched row
Close cursor
Deallocate cursor

What is the use of DBCC commands?
DBCC stands for database consistency checker. We use these commands to check the consistency of the databases, i.e., maintenance, validation task and status checks.
E.g. DBCC CHECKDB - Ensures that tables in the db and the indexes are correctly linked.
DBCC CHECKALLOC - To check that all pages in a db are correctly allocated.
DBCC CHECKFILEGROUP - Checks all tables file group for any damage.

What is a Linked Server?
Linked Servers is a concept in SQL Server by which we can add other SQL Server to a Group and query both the SQL Server dbs using T-SQL Statements. With a linked server, you can create very clean, easy to follow, SQL statements that allow remote data to be retrieved, joined and combined with local data.
Storped Procedure sp_addlinkedserver, sp_addlinkedsrvlogin will be used add new Linked Server.

What is Collation?
Collation refers to a set of rules that determine how data is sorted and compared. Character data is sorted using rules that define the correct character sequence, with options for specifying case-sensitivity, accent marks, kana character types and character width.

What are different type of Collation Sensitivity?
Case sensitivity
A and a, B and b, etc.

Accent sensitivity
a and á, o and ó, etc.

Kana Sensitivity
When Japanese kana characters Hiragana and Katakana are treated differently, it is called Kana sensitive.

Width sensitivity
When a single-byte character (half-width) and the same character when represented as a double-byte character (full-width) are treated differently then it is width sensitive.

What’s the difference between a primary key and a unique key?
Both primary key and unique enforce uniqueness of the column on which they are defined. But by default primary key creates a clustered index on the column, where are unique creates a nonclustered index by default. Another major difference is that, primary key doesn’t allow NULLs, but unique key allows one NULL only.

How to implement one-to-one, one-to-many and many-to-many relationships while designing tables?
One-to-One relationship can be implemented as a single table and rarely as two tables with primary and foreign key relationships.
One-to-Many relationships are implemented by splitting the data into two tables with primary key and foreign key relationships.
Many-to-Many relationships are implemented using a junction table with the keys from both the tables forming the composite primary key of the junction table.

What is a NOLOCK?
Using the NOLOCK query optimiser hint is generally considered good practice in order to improve concurrency on a busy system. When the NOLOCK hint is included in a SELECT statement, no locks are taken when data is read. The result is a Dirty Read, which means that another process could be updating the data at the exact time you are reading it. There are no guarantees that your query will retrieve the most recent data. The advantage to performance is that your reading of data will not block updates from taking place, and updates will not block your reading of data. SELECT statements take Shared (Read) locks. This means that multiple SELECT statements are allowed simultaneous access, but other processes are blocked from modifying the data. The updates will queue until all the reads have completed, and reads requested after the update will wait for the updates to complete. The result to your system is delay(blocking).

What is difference between DELETE & TRUNCATE commands?
Delete command removes the rows from a table based on the condition that we provide with a WHERE clause. Truncate will actually remove all the rows from a table and there will be no data in the table after we run the truncate command.

TRUNCATE
TRUNCATE is faster and uses fewer system and transaction log resources than DELETE.
TRUNCATE removes the data by deallocating the data pages used to store the table’s data, and only the page deallocations are recorded in the transaction log.
TRUNCATE removes all rows from a table, but the table structure and its columns, constraints, indexes and so on remain. The counter used by an identity for new rows is reset to the seed for the column.
You cannot use TRUNCATE TABLE on a table referenced by a FOREIGN KEY constraint.
Because TRUNCATE TABLE is not logged, it cannot activate a trigger.
TRUNCATE can not be Rolled back using logs.
TRUNCATE is DDL Command.
TRUNCATE Resets identity of the table.

DELETE
DELETE removes rows one at a time and records an entry in the transaction log for each deleted row.
If you want to retain the identity counter, use DELETE instead. If you want to remove table definition and its data, use the DROP TABLE statement.
DELETE Can be used with or without a WHERE clause
DELETE Activates Triggers.
DELETE Can be Rolled back using logs.
DELETE is DML Command.
DELETE does not reset identity of the table.

Difference between Function and Stored Procedure?
UDF can be used in the SQL statements anywhere in the WHERE/HAVING/SELECT section where as Stored procedures cannot be.
UDFs that return tables can be treated as another rowset. This can be used in JOINs with other tables.
Inline UDF’s can be though of as views that take parameters and can be used in JOINs and other Rowset operations.

When is the use of UPDATE_STATISTICS command?
This command is basically used when a large processing of data has occurred. If a large amount of deletions any modification or Bulk Copy into the tables has occurred, it has to update the indexes to take these changes into account. UPDATE_STATISTICS updates the indexes on these tables accordingly.

What types of Joins are possible with Sql Server?
Joins are used in queries to explain how different tables are related. Joins also let you select data from a table depending upon data from another table.
Types of joins: INNER JOINs, OUTER JOINs, CROSS JOINs. OUTER JOINs are further classified as LEFT OUTER JOINS, RIGHT OUTER JOINS and FULL OUTER JOINS.

What is the difference between a HAVING CLAUSE and a WHERE CLAUSE?
Specifies a search condition for a group or an aggregate. HAVING can be used only with the SELECT statement. HAVING is typically used in a GROUP BY clause. When GROUP BY is not used, HAVING behaves like a WHERE clause. Having Clause is basically used only with the GROUP BY function in a query. WHERE Clause is applied to each row before they are part of the GROUP BY function in a query. HAVING criteria is applied after the the grouping of rows has occurred.

What is sub-query? Explain properties of sub-query.
Sub-queries are often referred to as sub-selects, as they allow a SELECT statement to be executed arbitrarily within the body of another SQL statement. A sub-query is executed by enclosing it in a set of parentheses. Sub-queries are generally used to return a single row as an atomic value, though they may be used to compare values against multiple rows with the IN keyword.

A subquery is a SELECT statement that is nested within another T-SQL statement. A subquery SELECT statement if executed independently of the T-SQL statement, in which it is nested, will return a result set. Meaning a subquery SELECT statement can standalone and is not depended on the statement in which it is nested. A subquery SELECT statement can return any number of values, and can be found in, the column list of a SELECT statement, a FROM, GROUP BY, HAVING, and/or ORDER BY clauses of a T-SQL statement. A Subquery can also be used as a parameter to a function call. Basically a subquery can be used anywhere an expression can be used.

Properties of Sub-Query
A subquery must be enclosed in the parenthesis.
A subquery must be put in the right hand of the comparison operator, and
A subquery cannot contain a ORDER-BY clause.
A query can contain more than one sub-queries.

What are types of sub-queries?
Single-row subquery, where the subquery returns only one row.
Multiple-row subquery, where the subquery returns multiple rows,.and
Multiple column subquery, where the subquery returns multiple columns.

What is SQL Profiler?
SQL Profiler is a graphical tool that allows system administrators to monitor events in an instance of Microsoft SQL Server. You can capture and save data about each event to a file or SQL Server table to analyze later. For example, you can monitor a production environment to see which stored procedures are hampering performance by executing too slowly.

Use SQL Profiler to monitor only the events in which you are interested. If traces are becoming too large, you can filter them based on the information you want, so that only a subset of the event data is collected. Monitoring too many events adds overhead to the server and the monitoring process and can cause the trace file or trace table to grow very large, especially when the monitoring process takes place over a long period of time.

What is User Defined Functions?
User-Defined Functions allow to define its own T-SQL functions that can accept 0 or more parameters and return a single scalar data value or a table data type.

What kind of User-Defined Functions can be created?
There are three types of User-Defined functions in SQL Server 2000 and they are Scalar, Inline Table-Valued and Multi-statement Table-valued.

Scalar User-Defined Function
A Scalar user-defined function returns one of the scalar data types. Text, ntext, image and timestamp data types are not supported. These are the type of user-defined functions that most developers are used to in other programming languages. You pass in 0 to many parameters and you get a return value.

Inline Table-Value User-Defined Function
An Inline Table-Value user-defined function returns a table data type and is an exceptional alternative to a view as the user-defined function can pass parameters into a T-SQL select command and in essence provide us with a parameterized, non-updateable view of the underlying tables.

Multi-statement Table-Value User-Defined Function
A Multi-Statement Table-Value user-defined function returns a table and is also an exceptional alternative to a view as the function can support multiple T-SQL statements to build the final result where the view is limited to a single SELECT statement. Also, the ability to pass parameters into a T-SQL select command or a group of them gives us the capability to in essence create a parameterized, non-updateable view of the data in the underlying tables. Within the create function command you must define the table structure that is being returned. After creating this type of user-defined function, It can be used in the FROM clause of a T-SQL command unlike the behavior found when using a stored procedure which can also return record sets.

Which TCP/IP port does SQL Server run on? How can it be changed?
SQL Server runs on port 1433. It can be changed from the Network Utility TCP/IP properties –> Port number.both on client and the server.

What are the authentication modes in SQL Server? How can it be changed?
Windows mode and mixed mode (SQL & Windows).

To change authentication mode in SQL Server click Start, Programs, Microsoft SQL Server and click SQL Enterprise Manager to run SQL Enterprise Manager from the Microsoft SQL Server program group. Select the server then from the Tools menu select SQL Server Configuration Properties, and choose the Security page.

Where are SQL server users names and passwords are stored in sql server?
They get stored in master db in the sysxlogins table.

Which command using Query Analyzer will give you the version of SQL server and operating system?

SELECT  SERVERPROPERTY('productversion'), SERVERPROPERTY ('productlevel'), SERVERPROPERTY ('edition')

What is SQL server agent?
SQL Server agent plays an important role in the day-to-day tasks of a database administrator (DBA). It is often overlooked as one of the main tools for SQL Server management. Its purpose is to ease the implementation of tasks for the DBA, with its full-function scheduling engine, which allows you to schedule your own jobs and scripts.

Can a stored procedure call itself or recursive stored procedure? How many level SP nesting possible?
Yes. Because Transact-SQL supports recursion, you can write stored procedures that call themselves. Recursion can be defined as a method of problem solving wherein the solution is arrived at by repetitively applying it to subsets of the problem. A common application of recursive logic is to perform numeric computations that lend themselves to repetitive evaluation by the same processing steps. Stored procedures are nested when one stored procedure calls another or executes managed code by referencing a CLR routine, type, or aggregate. You can nest stored procedures and managed code references up to 32 levels.

What is @@ERROR?
The @@ERROR automatic variable returns the error code of the last Transact-SQL statement. If there was no error, @@ERROR returns zero. Because @@ERROR is reset after each Transact-SQL statement, it must be saved to a variable if it is needed to process it further after checking it.

What is Raiseerror?
Stored procedures report errors to client applications via the RAISERROR command. RAISERROR doesn’t change the flow of a procedure; it merely displays an error message, sets the @@ERROR automatic variable, and optionally writes the message to the SQL Server error log and the NT application event log.

What is log shipping?
Log shipping is the process of automating the backup of database and transaction log files on a production SQL server, and then restoring them onto a standby server. Enterprise Editions only supports log shipping. In log shipping the transactional log file from one server is automatically updated into the backup database on the other server. If one server fails, the other server will have the same db can be used this as the Disaster Recovery plan. The key feature of log shipping is that is will automatically backup transaction logs throughout the day and automatically restore them on the standby server at defined interval.

What is the difference between a local and a global variable?
A local temporary table exists only for the duration of a connection or, if defined inside a compound statement, for the duration of the compound statement.

A global temporary table remains in the database permanently, but the rows exist only within a given connection. When connection are closed, the data in the global temporary table disappears. However, the table definition remains with the database for access when database is opened next time.

What command do we use to rename a db?
sp_renamedb ‘oldname’ , ‘newname’
If someone is using db it will not accept sp_renmaedb. In that case first bring db to single user using sp_dboptions. Use sp_renamedb to rename database. Use sp_dboptions to bring database to multi user mode.

What is sp_configure commands and set commands?
Use sp_configure to display or change server-level settings. To change database-level settings, use ALTER DATABASE. To change settings that affect only the current user session, use the SET statement.

What are the different types of replication? Explain.
The SQL Server 2000-supported replication types are as follows:

  • Transactional
  • Snapshot
  • Merge

Snapshot replication distributes data exactly as it appears at a specific moment in time and does not monitor for updates to the data. Snapshot replication is best used as a method for replicating data that changes infrequently or where the most up-to-date values (low latency) are not a requirement. When synchronization occurs, the entire snapshot is generated and sent to Subscribers.

Transactional replication, an initial snapshot of data is applied at Subscribers, and then when data modifications are made at the Publisher, the individual transactions are captured and propagated to Subscribers.

Merge replication is the process of distributing data from Publisher to Subscribers, allowing the Publisher and Subscribers to make updates while connected or disconnected, and then merging the updates between sites when they are connected.

What are the OS services that the SQL Server installation adds?
MS SQL SERVER SERVICE, SQL AGENT SERVICE, DTC (Distribution transac co-ordinator)

What are three SQL keywords used to change or set someone’s permissions?
GRANT, DENY, and REVOKE.

What does it mean to have quoted_identifier on? What are the implications of having it off?
When SET QUOTED_IDENTIFIER is ON, identifiers can be delimited by double quotation marks, and literals must be delimited by single quotation marks. When SET QUOTED_IDENTIFIER is OFF, identifiers cannot be quoted and must follow all Transact-SQL rules for identifiers.

What is the STUFF function and how does it differ from the REPLACE function?
STUFF function to overwrite existing characters. Using this syntax, STUFF(string_expression, start, length, replacement_characters), string_expression is the string that will have characters substituted, start is the starting position, length is the number of characters in the string that are substituted, and replacement_characters are the new characters interjected into the string.
REPLACE function to replace existing characters of all occurance. Using this syntax REPLACE(string_expression, search_string, replacement_string), where every incidence of search_string found in the string_expression will be replaced with replacement_string.

Using query analyzer, name 3 ways to get an accurate count of the number of records in a table?
SELECT * FROM table1
SELECT COUNT(*) FROM table1
SELECT rows FROM sysindexes WHERE id = OBJECT_ID(table1) AND indid <>

How to rebuild Master Database?
Shutdown Microsoft SQL Server 2000, and then run Rebuildm.exe. This is located in the Program Files\Microsoft SQL Server\80\Tools\Binn directory.
In the Rebuild Master dialog box, click Browse.
In the Browse for Folder dialog box, select the \Data folder on the SQL Server 2000 compact disc or in the shared network directory from which SQL Server 2000 was installed, and then click OK.
Click Settings. In the Collation Settings dialog box, verify or change settings used for the master database and all other databases.
Initially, the default collation settings are shown, but these may not match the collation selected during setup. You can select the same settings used during setup or select new collation settings. When done, click OK.
In the Rebuild Master dialog box, click Rebuild to start the process.
The Rebuild Master utility reinstalls the master database.
To continue, you may need to stop a server that is running.
Source: http://msdn2.microsoft.com/en-us/library/aa197950(SQL.80).aspx

What is the basic functions for master, msdb, model, tempdb databases?
The Master database holds information for all databases located on the SQL Server instance and is the glue that holds the engine together. Because SQL Server cannot start without a functioning master database, you must administer this database with care.
The msdb database stores information regarding database backups, SQL Agent information, DTS packages, SQL Server jobs, and some replication information such as for log shipping.
The tempdb holds temporary objects such as global and local temporary tables and stored procedures.
The model is essentially a template database used in the creation of any new user database created in the instance.

What are primary keys and foreign keys?
Primary keys are the unique identifiers for each row. They must contain unique values and cannot be null. Due to their importance in relational databases, Primary keys are the most fundamental of all keys and constraints. A table can have only one Primary key.
Foreign keys are both a method of ensuring data integrity and a manifestation of the relationship between tables.

What is data integrity? Explain constraints?
Data integrity is an important feature in SQL Server. When used properly, it ensures that data is accurate, correct, and valid. It also acts as a trap for otherwise undetectable bugs within applications.
A PRIMARY KEY constraint is a unique identifier for a row within a database table. Every table should have a primary key constraint to uniquely identify each row and only one primary key constraint can be created for each table. The primary key constraints are used to enforce entity integrity.

A UNIQUE constraint enforces the uniqueness of the values in a set of columns, so no duplicate values are entered. The unique key constraints are used to enforce entity integrity as the primary key constraints.

A FOREIGN KEY constraint prevents any actions that would destroy links between tables with the corresponding data values. A foreign key in one table points to a primary key in another table. Foreign keys prevent actions that would leave rows with foreign key values when there are no primary keys with that value. The foreign key constraints are used to enforce referential integrity.

A CHECK constraint is used to limit the values that can be placed in a column. The check constraints are used to enforce domain integrity.

A NOT NULL constraint enforces that the column will not accept null values. The not null constraints are used to enforce domain integrity, as the check constraints.

What are the properties of the Relational tables?
Relational tables have six properties:

  • Values are atomic.
  • Column values are of the same kind.
  • Each row is unique.
  • The sequence of columns is insignificant.
  • The sequence of rows is insignificant.
  • Each column must have a unique name.

What is De-normalization?
De-normalization is the process of attempting to optimize the performance of a database by adding redundant data. It is sometimes necessary because current DBMSs implement the relational model poorly. A true relational DBMS would allow for a fully normalized database at the logical level, while providing physical storage of data that is tuned for high performance. De-normalization is a technique to move from higher to lower normal forms of database modeling in order to speed up database access.

How to get @@error and @@rowcount at the same time?
If @@Rowcount is checked after Error checking statement then it will have 0 as the value of @@Recordcount as it would have been reset.
And if @@Recordcount is checked before the error-checking statement then @@Error would get reset. To get @@error and @@rowcount at the same time do both in same statement and store them in local variable. SELECT @RC = @@ROWCOUNT, @ER = @@ERROR

What is Identity?
Identity (or AutoNumber) is a column that automatically generates numeric values. A start and increment value can be set, but most DBA leave these at 1. A GUID column also generates numbers, the value of this cannot be controled. Identity/GUID columns do not need to be indexed.

What is a Scheduled Jobs or What is a Scheduled Tasks?
Scheduled tasks let user automate processes that run on regular or predictable cycles. User can schedule administrative tasks, such as cube processing, to run during times of slow business activity. User can also determine the order in which tasks run by creating job steps within a SQL Server Agent job. E.g. Back up database, Update Stats of Tables. Job steps give user control over flow of execution. If one job fails, user can configure SQL Server Agent to continue to run the remaining tasks or to stop execution.

What is a table called, if it does not have neither Cluster nor Non-cluster Index? What is it used for?
Unindexed table or Heap. Microsoft Press Books and Book On Line (BOL) refers it as Heap.
A heap is a table that does not have a clustered index and, therefore, the pages are not linked by pointers. The IAM pages are the only structures that link the pages in a table together.
Unindexed tables are good for fast storing of data. Many times it is better to drop all indexes from table and than do bulk of inserts and to restore those indexes after that.

What is BCP? When does it used?
BulkCopy is a tool used to copy huge amount of data from tables and views. BCP does not copy the structures same as source to destination.

How do you load large data to the SQL server database?
BulkCopy is a tool used to copy huge amount of data from tables. BULK INSERT command helps to Imports a data file into a database table or view in a user-specified format.

Can we rewrite subqueries into simple select statements or with joins?
Subqueries can often be re-written to use a standard outer join, resulting in faster performance. As we may know, an outer join uses the plus sign (+) operator to tell the database to return all non-matching rows with NULL values. Hence we combine the outer join with a NULL test in the WHERE clause to reproduce the result set without using a sub-query.

Can SQL Servers linked to other servers like Oracle?
SQL Server can be lined to any server provided it has OLE-DB provider from Microsoft to allow a link. E.g. Oracle has a OLE-DB provider for oracle that Microsoft provides to add it as linked server to SQL Server group.

How to know which index a table is using?
SELECT table_name,index_name FROM user_constraints

How to copy the tables, schema and views from one SQL server to another?
Microsoft SQL Server 2000 Data Transformation Services (DTS) is a set of graphical tools and programmable objects that lets user extract, transform, and consolidate data from disparate sources into single or multiple destinations.

What is Self Join?
This is a particular case when one table joins to itself, with one or two aliases to avoid confusion. A self join can be of any type, as long as the joined tables are the same. A self join is rather unique in that it involves a relationship with only one table. The common example is when company have a hierarchal reporting structure whereby one member of staff reports to another.

What is Cross Join?
A cross join that does not have a WHERE clause produces the Cartesian product of the tables involved in the join. The size of a Cartesian product result set is the number of rows in the first table multiplied by the number of rows in the second table. The common example is when company wants to combine each product with a pricing table to analyze each product at each price.

Which virtual table does a trigger use?
Inserted and Deleted.

List few advantages of Stored Procedure.

  • Stored procedure can reduced network traffic and latency, boosting application performance.
  • Stored procedure execution plans can be reused, staying cached in SQL Server’s memory, reducing server overhead.
  • Stored procedures help promote code reuse.
  • Stored procedures can encapsulate logic. You can change stored procedure code without affecting clients.
  • Stored procedures provide better security to your data.

What is DataWarehousing?

  • Subject-oriented, meaning that the data in the database is organized so that all the data elements relating to the same real-world event or object are linked together;
  • Time-variant, meaning that the changes to the data in the database are tracked and recorded so that reports can be produced showing changes over time;
  • Non-volatile, meaning that data in the database is never over-written or deleted, once committed, the data is static, read-only, but retained for future reporting;
  • Integrated, meaning that the database contains data from most or all of an organization’s operational applications, and that this data is made consistent.

What is OLTP(OnLine Transaction Processing)?
In OLTP - online transaction processing systems relational database design use the discipline of data modeling and generally follow the Codd rules of data normalization in order to ensure absolute data integrity. Using these rules complex information is broken down into its most simple structures (a table) where all of the individual atomic level elements relate to each other and satisfy the normalization rules.

How do SQL server 2000 and XML linked? Can XML be used to access data?
FOR XML (ROW, AUTO, EXPLICIT)
You can execute SQL queries against existing relational databases to return results as XML rather than standard rowsets. These queries can be executed directly or from within stored procedures. To retrieve XML results, use the FOR XML clause of the SELECT statement and specify an XML mode of RAW, AUTO, or EXPLICIT.

OPENXML
OPENXML is a Transact-SQL keyword that provides a relational/rowset view over an in-memory XML document. OPENXML is a rowset provider similar to a table or a view. OPENXML provides a way to access XML data within the Transact-SQL context by transferring data from an XML document into the relational tables. Thus, OPENXML allows you to manage an XML document and its interaction with the relational environment.

What is an execution plan? When would you use it? How would you view the execution plan?
An execution plan is basically a road map that graphically or textually shows the data retrieval methods chosen by the SQL Server query optimizer for a stored procedure or ad-hoc query and is a very useful tool for a developer to understand the performance characteristics of a query or stored procedure since the plan is the one that SQL Server will place in its cache and use to execute the stored procedure or query. From within Query Analyzer is an option called “Show Execution Plan” (located on the Query drop-down menu). If this option is turned on it will display query execution plan in separate window when query is ran again.

Wednesday, August 22, 2007

.NET Interview Questions

UML
What is UML?
How many types of diagrams are there in UML ?
Twist :- Explain in short all types of diagrams in UML ?
What are advantages of using UML?
Twist: - What is Modeling and why UML ?
What’s the sequence of UML diagrams in project?
Twist: - How did you implement UML in your project?
Just a small Twist: - Do I need all UML diagrams in a project?
Give a small brief explanation of all Elements in activity diagrams?
Explain Different elements of a collaboration diagram ?
Explain Component diagrams ?
Explain all parts of a deployment diagram?
Describe various components in sequence diagrams?
What are the element in State Chart diagrams ?
Describe different elements in Static Chart diagrams ?
Explain different elements of a Use Case ?
Twist: - What’s difference between Activity and sequence diagrams?(I leave this to the
readers)

.NET Interoperability
How can we use COM Components in .NET?
Twist : What is RCW ?
Once i have developed the COM wrapper do i have to still register the COM in registry?
How can we use .NET components in COM?
Twist :- What is CCW (COM callable wrapper) ?, What caution needs to be taken in order
that .NET components is compatible with COM ?
How can we make Windows API calls in .NET?
When we use windows API in .NET is it managed or unmanaged code ?
What is COM ?
What is Reference counting in COM ?
Can you describe IUKNOWN interface in short ?
Can you explain what is DCOM ?
How do we create DCOM object in VB6?
How to implement DTC in .NET ?
How many types of Transactions are there in COM + .NET ?
How do you do object pooling in .NET ?
What are types of compatibility in VB6?
What is equivalent for regsvr32 exe in .NET ?

Threading
What is Multi-tasking ?
What is Multi-threading ?
What is a Thread ?
Did VB6 support multi-threading ?
Can we have multiple threads in one App domain ?
Which namespace has threading ?
Can you explain in brief how can we implement threading ?
How can we change priority and what the levels of priority are provided by .NET ?
What does Addressof operator do in background ?
How can you reference current thread of the method ?
What's Thread.Sleep() in threading ?
How can we make a thread sleep for infinite period ?
What is Suspend and Resume in Threading ?
What the way to stop a long running thread ?
How do i debug thread ?
What's Thread.Join() in threading ?
What are Daemon thread's and how can a thread be created as Daemon?
When working with shared data in threading how do you implement synchronization ?
Can we use events with threading ?
How can we know a state of a thread?
What is a monitor object?
What are wait handles ?
Twist :- What is a mutex object ?
what is ManualResetEvent and AutoResetEvent ?
What is ReaderWriter Locks ?
How can you avoid deadlock in threading ?
What’s difference between thread and process?

Remoting and Webservices
What is a application domain?
What is .NET Remoting ?
Which class does the remote object has to inherit ?
What are two different types of remote object creation mode in .NET ?
Describe in detail Basic of SAO architecture of Remoting?
What are the situations you will use singleton architecture in remoting ?
What is fundamental of published or precreated objects in Remoting ?
What are the ways client can create object on server in CAO model ?
Are CAO stateful in nature ?
In CAO model when we want client objects to be created by “NEW” keyword is there
any precautions to be taken ?
Is it a good design practice to distribute the implementation to Remoting Client ?
What is LeaseTime,SponsorshipTime ,RenewonCallTime and LeaseManagerPollTime?
Which config file has all the supported channels/protocol ?
How can you specify remoting parameters using Config files ?
Can Non-Default constructors be used with Single Call SAO?
Twist :- What are the limitation of constructors for Single call SAO ?
How can we call methods in remoting Asynchronously ?
What is Asynchronous One-Way Calls ?
What is marshalling and what are different kinds of marshalling ?
What is ObjRef object in remoting ?
What is a WebService ?
What is UDDI ?
What is DISCO ?
What is WSDL?
What the different phase/steps of acquiring a proxy object in Webservice ?
What is file extension of Webservices ?
Which attribute is used in order that the method can be used as WebService ?
What are the steps to create a webservice and consume it ?
Do webservice have state ?

Caching Concepts
What is application object ?
What’s the difference between Cache object and application object ?
How can get access to cache object ?
What are dependencies in cache and types of dependencies ?
Can you show a simple code showing file dependency in cache ?
What is Cache Callback in Cache ?
What is scavenging ?
What are different types of caching using cache object of ASP.NET?
How can you cache different version of same page using ASP.NET cache object ?
How will implement Page Fragment Caching ?
What are ASP.NET session and compare ASP.NET session with classic ASP session
variables?
Which various modes of storing ASP.NET session ?
Is Session_End event supported in all session modes ?
What are the precautions you will take in order that StateServer Mode work properly ?
What are the precautions you will take in order that SQLSERVER Mode work properly ?
Where do you specify session state mode in ASP.NET ?
What are the other ways you can maintain state ?
What are benefits and Limitation of using Hidden fields ?
What is ViewState ?
Do performance vary for viewstate according to User controls ?
What are benefits and Limitation of using Viewstate for state management?
How an you use Hidden frames to cache client data ?
What are benefits and Limitation of using Hidden frames?
What are benefits and Limitation of using Cookies?
What is Query String and What are benefits and Limitation of using Query Strings?

OOPS
What is Object Oriented Programming ?
What’s a Class ?
What’s a Object ?
What’s the relation between Classes and Objects ?
What are different properties provided by Object-oriented systems ?
Twist :- Can you explain different properties of Object Oriented Systems?
Twist :- What’s difference between Association , Aggregation and Inheritance relationships?
How can we acheive inheritance in VB.NET ?
What are abstract classes ?
What’s a Interface ?
What is difference between abstract classes and interfaces?
What is a delegate ?
What are event’s ?
Do events have return type ?
Can event’s have access modifiers ?
Can we have shared events ?
What is shadowing ?
What’s difference between Shadowing and Overriding ?
What’s difference between delegate and events?
If we inherit a class do the private variables also get inherited ?
What are different accessibility levels defined in .NET ?
Can you prevent a class from overriding ?
What’s the use of “MustInherit” keyword in VB.NET ?
Why can not you specify accessibility modifier in Interface ?
What are similarities between Class and structure ?
What’s the difference between Class and structure’s ?
What does virtual keyword mean ?
What are shared (VB.NET)/Static(C#) variables?
What is Dispose method in .NET ?
Whats the use of “OverRides” and “Overridable” keywords ?
Where are all .NET Collection classes located ?
What is ArrayList ?
What’s a HashTable ?
Twist :- What’s difference between HashTable and ArrayList ?
What are queues and stacks ?
What is ENUM ?
What is nested Classes ?
What’s Operator Overloading in .NET?
In below sample code if we create a object of class2 which constructor will fire first ?
What’s the significance of Finalize method in .NET?
Why is it preferred to not use finalize for clean up?
How can we suppress a finalize method?
What’s the use of DISPOSE method?
How do I force the Dispose method to be called automatically, as clients can forget to call
Dispose method?
In what instances you will declare a constructor to be private?
Can we have different access modifiers on get/set methods of a property ?
If we write a goto or a return statement in try and catch block will the finally block
execute ?
What is Indexer ?
Can we have static indexer in C# ?
In a program there are multiple catch blocks so can it happen that two catch blocks are
executed ?
What is the difference between System.String and System.StringBuilder classes?

ASP.NET
What’s the sequence in which ASP.NET events are processed ?
In which event are the controls fully loaded ?
How can we identify that the Page is PostBack ?
How does ASP.NET maintain state in between subsequent request ?
What is event bubbling ?
How do we assign page specific attributes ?
Administrator wants to make a security check that no one has tampered with ViewState
, how can he ensure this ? 153
What’s the use of @ Register directives ?
What’s the use of SmartNavigation property ?
What is AppSetting Section in “Web.Config” file ?
Where is ViewState information stored ?
What’s the use of @ OutputCache directive in ASP.NET?
How can we create custom controls in ASP.NET ?
How many types of validation controls are provided by ASP.NET ?
Can you explain what is “AutoPostBack” feature in ASP.NET ?
How can you enable automatic paging in DataGrid ?
What’s the use of “GLOBAL.ASAX” file ?
What’s the difference between “Web.config” and “Machine.Config” ?
What’s a SESSION and APPLICATION object ?
What’s difference between Server.Transfer and response.Redirect ?
What’s difference between Authentication and authorization?
What is impersonation in ASP.NET ?
Can you explain in brief how the ASP.NET authentication process works?
What are the various ways of authentication techniques in ASP.NET?
How does authorization work in ASP.NET?
What’s difference between Datagrid , Datalist and repeater ?
From performance point of view how do they rate ?
What’s the method to customize columns in DataGrid?
How can we format data inside DataGrid?
How will decide the design consideration to take a Datagrid , datalist or repeater ?
Difference between ASP and ASP.NET?
What are major events in GLOBAL.ASAX file ?
What order they are triggered ?
Do session use cookies ?
How can we force all the validation control to run ?
How can we check if all the validation control are valid and proper ?
If you have client side validation is enabled in your Web page , Does that mean server
side code is not run?
Which JavaScript file is referenced for validating the validators at the client side ?
How to disable client side script in validators?
I want to show the entire validation error message in a message box on the client side?
You find that one of your validation is very complicated and does not fit in any of the
validators , so what will you do ?
What is Tracing in ASP.NET ?
How do we enable tracing ?
What exactly happens when ASPX page is requested from Browser?
How can we kill a user session ?
How do you upload a file in ASP.NET ?
How do I send email message from ASP.NET ?
What are different IIS isolation levels?
ASP used STA threading model , whats the threading model used for ASP.NET ?
Whats the use of attribute ?
Explain the differences between Server-side and Client-side code?
Can you explain Forms authentication in detail ?
How do I sign out in forms authentication ?
If cookies are not enabled at browser end does form Authentication work?
How to use a checkbox in a datagrid?
What are the steps to create a windows service in VB.NET ?
What’s the difference between “Web farms” and “Web garden”?
How do we configure “WebGarden”?
What is the main difference between Gridlayout and FlowLayout ?

.NET Architecture
What are design patterns ?
What’s difference between Factory and Abstract Factory Pattern’s?
What’s MVC pattern?
Twist: - How can you implement MVC pattern in ASP.NET?
How can we implement singleton pattern in .NET?
How do you implement prototype pattern in .NET?
Twist: - How to implement cloning in .NET ? , What is shallow copy and deep copy ?
What are the situations you will use a Web Service and Remoting in projects?
Can you give a practical implementation of FAÇADE patterns?
How can we implement observer pattern in .NET?
What is three tier architecture?
Have you ever worked with Microsoft Application Blocks, if yes then which?
What is Service Oriented architecture?
What are different ways you can pass data between tiers?
What is Windows DNA architecture?
What is aspect oriented programming?

ADO.NET
What is the namespace in which .NET has the data functionality classes ?
Can you give a overview of ADO.NET architecture ?
What are the two fundamental objects in ADO.NET ?
What is difference between dataset and datareader ?
What are major difference between classic ADO and ADO.NET ?
What is the use of connection object ?
What is the use of command objects and what are the methods provided by the command
object ?
What is the use of dataadapter ?
What are basic methods of Dataadapter ?
What is Dataset object?
What are the various objects in Dataset ?
How can we connect to Microsoft Access , Foxpro , Oracle etc ?
How do we connect to SQL SERVER , which namespace do we use ?
How do we use stored procedure in ADO.NET and how do we provide parameters to
the stored procedures?
How can we force the connection object to close after my datareader is closed ?
I want to force the datareader to return only schema of the datastore rather than data ?
How can we fine tune the command object when we are expecting a single row or a single
value ?
Which is the best place to store connectionstring in .NET projects ?
What are steps involved to fill a dataset ?
Twist :- How can we use dataadapter to fill a dataset ?
What are the various methods provided by the dataset object to generate XML?
How can we save all data from dataset ?
How can we check that some changes have been made to dataset since it was loaded ?
Twist :- How can we cancel all changes done in dataset ? , How do we get values which
are changed in a dataset ?
How can we add/remove row’s in “DataTable” object of “DataSet” ?
What’s basic use of “DataView” ?
What’s difference between “DataSet” and “DataReader” ?
Twist :- Why is DataSet slower than DataReader ?
How can we load multiple tables in a DataSet ?
How can we add relation’s between table in a DataSet ?
What’s the use of CommandBuilder ?
What’s difference between “Optimistic” and “Pessimistic” locking ?
How many way’s are there to implement locking in ADO.NET ?
How can we perform transactions in .NET?
What’s difference between Dataset. clone and Dataset. copy ?
Can you explain the difference between an ADO.NET Dataset and an ADO Recordset?
Explain in detail the fundamental of connection pooling?
What is Maximum Pool Size in ADO.NET Connection String?
How to enable and disable connection pooling?

SQL SERVER

What is normalization? What are different type of normalization?
What is denormalization ?
What is a candidate key ?
What are different types of joins and whats the difference between them ?
What are indexes and What is the difference between clustered and nonclustered indexes?
How can you increase SQL performance ?
What is the use of OLAP ?
What's a measure in OLAP ?
What are dimensions in OLAP ?
What are levels in dimensions ?
What are fact tables and dimension tables in OLAP ?
Twist :- can you explain the star schema for OLAP ?
What is DTS?
What is fillfactor ?
Twist :- When does plage split occurs ?
What is RAID and how does it work ?
What's the difference between DELETE TABLE and TRUNCATE TABLE commands?
What are the problems that can occur if you do not implement locking properly in SQL
SERVER ?
What are different transaction levels in SQL SERVER ?
Twist :- what are different types of locks in SQL SERVER ?
What are different locks in SQL SERVER ?
Can we suggest locking hints to SQL SERVER ?
What is LOCK escalation?
What are the different ways of moving data/databases between servers and databases in
SQL Server?
What are advantages of SQL 2000 over SQl 7.0 ?
What is the difference between a HAVING CLAUSE and a WHERE CLAUSE?
What is difference between UNION and UNION ALL SQL syntax ?
How can you raise custom errors from stored procedure ?
What is ACID fundamental and what are transactions in SQL SERVER ?
What is DBCC?
What is purpose of Replication ?
What are different type of replication supported by SQL SERVER ?
What is BCP utility in SQL SERVER ?
What are different types of triggers in SQl SERVER 2000 ?
If we have multiple AFTER Triggers on table how can we define the sequence of the
triggers ?
What is SQl injection ?
What’s the difference between Stored Procedure (SP) and User Defined Function (UDF)?

Project Management
What is project management?
Is spending in IT project’s constant through out the project?
Who is a stakeholder ?
Can you explain project life cycle ?
Twist :- How many phases are there in software project ?
Are risk constant through out the project ?
Can you explain different software development life cycles ?
What is triple constraint triangle in project management ?
What is a project baselines ?
What is effort variance?
How is normally a project management plan document organized ?
How do you estimate a project?
What is CAR (Causal Analysis and Resolution)?
What is DAR (Decision Analysis and Resolution)?
What is a fish bone diagram ?
Twist:- What is Ishikawa diagram ?
What is pareto principle ?
Twist :- What is 80/20 principle ?
How do you handle change request?
What is internal change request?
What is difference between SITP and UTP in testing ?
What are the software you have used for project management?
What are the metrics followed in project management?
Twist: - What metrics will you look at in order to see the project is moving successfully?
You have people in your team who do not meet there deadlines or do not perform what
are the actions you will take ?
Twist :- Two of your resources have conflict’s between them how would you sort it out ?
What is black box testing and White box testing?
What’s the difference between Unit Testing, Assembly Testing and Regression testing?
What is V model in testing?
How do you start a project?
How did you do resource allocations?
How do you do code reviews ?
What is CMMI?
What are the five levels in CMMI?
What is continuous and staged representation?
Can you explain the process areas?
What is SIX sigma?
What is DMAIC and DMADV ?
What are the various roles in Six Sigma implementation?
What are function points?
Twist: - Define Elementary process in FPA?
What are different types of elementary process in FPA?
What are the different elements in Functions points?
Can you explain in GSC and VAF in function points?
What are unadjusted function points and how is it calculated?
Can you explain steps in function points?
What is the FP per day in your current company?
Twist :- What is your company’s productivity factor ?
Do you know Use Case points?
What is COCOMO I, COCOMOII and COCOMOIII?
What is SMC approach of estimation?
How do you estimate maintenance project and change requests?

XML
What is XML?
What is the version information in XML?
What is ROOT element in XML?
If XML does not have closing tag will it work?
Is XML case sensitive?
What’s the difference between XML and HTML?
Is XML meant to replace HTML?
Can you explain why your project needed XML?
What is DTD (Document Type definition)?
What is well formed XML?
What is a valid XML?
What is CDATA section in XML?
What is CSS?
What is XSL?
What is Element and attributes in XML?
Which are the namespaces in .NET used for XML?
What are the standard ways of parsing XML document?
In What scenarios will you use a DOM parser and SAX parser?
How was XML handled during COM times?
What’s the main difference between MSML and .NET Framework XML classes?
What are the core functionalities in XML .NET framework? Can you explain in detail
those functionalities?
What is XSLT?
Define XPATH?
What’s the concept of XPOINTER?
What is an XMLReader Class?
What is XMLTextReader?
How do we access attributes using “XmlReader”?
Explain simple Walk through of XmlReader ?
What does XmlValidatingReader class do?

What is garbage collection?
Can we force garbage collector to run ?
What is reflection?
What are different type of JIT ?
What are Value types and Reference types ?
What is concept of Boxing and Unboxing ?
What’s difference between VB.NET and C# ?
What’s difference between System exceptions and Application exceptions?
What is CODE Access security?
What is a satellite assembly?
How to prevent my .NET DLL to be decompiled?
What’s the difference between Convert.toString and .toString() method ?
What is Native Image Generator (Ngen.exe)?
We have two version of the same assembly in GAC? I want my client to make choice of
which assembly to choose?
What is CodeDom?

Tuesday, August 21, 2007

JAVA Interview Questions

OOPS and CORE JAVA
What is JVM (Java Virtual Machine)?
What is JIT (Just-in-Time) Compilation?
What is Object Oriented Programming?
What’s a Class?
What’s an Object?
What’s the relation between Classes and Objects?
What are different properties provided by Object-oriented systems?
How do you implement inheritance in Java?
How can we implement polymorphism in Java?
What’s an interface and how will you go about implementing an interface?
What is an Abstract class?
What are Abstract methods?
What’s the difference between “Abstract” classes and “Interfaces”?
What’s difference between Static and Non-Static fields of a class?
What are inner classes and what’s the practical implementation of inner classes?
What are packages?
What is a constructor in class?
Can constructors be parameterized?
Can you explain transient and volatile modifiers?
What is the use if “instanceof ” keyword?
What are Native methods in Java?
Explain in depth Garbage collector?
How does the garbage collector determine that the object has to be marked for deletion?
Can you explain “finalize()” method?
How can we force the garbage collector to run?
What’s the main difference between “Switch” and “If ” comparison?
What’s the use of JAVAP tool?
What are applets?
In which package is the applet class located?
What are native interfaces in Java?
what are Class loader’s?
what is Bootstrap, Extension and System Class loader?
Can you explain the flow between bootstrap, extension and system class loader?
Can you explain how can you practically do dynamic loading?
How can you copy one array in to a different array?
Can you explain the core collection interfaces?
Can you explain in brief the collection classes which implement the collection interfaces?
What’s the difference between standard JAVA array and ArrayList class?
What’s the use of “ensureCapacity” in ArrayList class?
How can we obtain an array from an ArrayList class?
What is “LinkedList” class for?
Can you explain HashSet class in collections?
what is LinkedHashSet class?
what is a TreeSet class?
what’s the use of Comparator Interface?
How can we access elements of a collection?
What is Map and SortedMap Interface?
Have you used any collection algorithm?
Why do we use collections when we had traditional ways for collection?
Can you name the legacy classes and interface for collections?
What is Enumeration Interface?
what’s the main difference between ArrayList / HashMap and Vector / Hashtable?
Are String object Immutable, Can you explain the concept?
what is a StringBuffer class and how does it differs from String class?
what is the difference between StringBuilder and StringBuffer class?
What is Pass by Value and Pass by reference? How does JAVA handle the same?
What are access modifiers?
what is Assertion?
Can you explain the fundamentals of deep and shallow Cloning?
How do we implement Shallow cloning?
How do we implement deep cloning?
What’s the impact of private constructor?
What are the situations you will need a constructor to be private?
Can you explain final modifier?
What are static Initializers?
If we have multiple static initializer blocks how is the sequence handled?
Define casting? What are the different types of Casting?
Can you explain Widening conversion and Narrowing conversion?
Can we assign parent object to child objects?
Define exceptions?
Can you explain in short how JAVA exception handling works?
Can you explain different exception types?
Can you explain checked and unchecked exceptions?
Can we create our own exception class?
What are chained exceptions?
What is serialization?
How do we implement serialization actually?
What’s the use of Externalizable Interface?
Threading
What’s difference between thread and process?
What is thread safety and synchronization?
What is semaphore?
What are monitors?
What’s the importance of synchronized blocks?
How do we create threads?
what’s the difference in using runnable and extends in threads?
Can you explain Thread.sleep?
How to stop a thread?
What is wait() and notify() ?
Can you explain how Scheduling and Priority works in threads?
Can you explain Yielding in threading?
what are daemon threads?
JDBC
How does JAVA interact with databases?
Can we interact with non-relational sources using JDBC?
Can you explain in depth the different sections in JDBC?
Can you explain in short how you go about using JDBC API in code?
How do you handle SQL exceptions?
If there is more than one exception in SQLException” class how to go about displaying
it?
Explain Type1, Type2, Type3 and Type4 drivers in JDBC?
What are the advantages and disadvantages of using JDBC-ODBC bridge driver?
What are the advantages and disadvantages of using Native-API/ Partially Java Driver?
What are the advantages and disadvantages of using Net-Protocol/ All-Java driver?
What are the advantages and disadvantages of using Native-protocol/ All-Java driver?
Define meta-data?
What is DatabaseMetaData?
Can you explain “ConnectionFactory” class?
I want to display tables of a database how do I do it?
Define “ResultSetMetaData”?
What is the difference between “ResultSet” and “RowSet”?
Can “ResultSet” objects be serialized?
Can you explain “ResultSet”, “RowSet”, “CachedRowset”, “JdbcRowset” and
“WebRowSet” relation ship?
what are the different types of resultset?
Explain the concept of “PreparedStatement “statement interface?
What’s the difference between “Statement” and “PreparedStatement”?
How can we call stored procedure using JDBC?
Can you explain “CallableStatement” interface in detail?
How do you get a resultset object from stored procedure?
How can we do batch updates using “CallableStatement” Interface?
Define transactions?
What is ACID in transaction?
What are the four essential properties of a transaction?
Explain concurrency and locking?
What are different types of locks?
What are the different types of levels of resource on which locks can be placed?
Define lock escalation?
What is Table level and Row level locking?
What are the problems that can occur if you do not implement locking properly?
What are different transaction levels?
Twist: - what are different types of locks?
What is difference between optimistic and pessimistic locking?
What are deadlocks?
How can we set transaction level through JDBC API?
Can you explain transaction control in JDBC?
What are Savepoints in a transaction?
Servlets and JSP
What are Servlets?
What are advantages of servlets over CGI?
Can you explain Servlet life cycle?
What are the two important API’s in for Servlets?
Can you explain in detail “javax.servlet” package?
What’s the use of ServletContext?
How do we define an application level scope for servlet?
What's the difference between GenericServlet and HttpServlet?
Can you explain in detail javax.servlet.http package?
What’s the architecture of a Servlet package?
Why is HTTP protocol called as a stateless protocol?
What are the different ways we can maintain state between requests?
What is URL rewriting?
What are cookies?
What are sessions in Servlets?
What’s the difference between getSession(true) and getSession(false) ?
What’s the difference between “doPost” and “doGet” methods?
Which are the different ways you can communicate between servlets?
What is functionality of “RequestDispatcher” object?
How do we share data using “getServletContext ()”?
Explain the concept of SSI?
What are filters in JAVA?
Can you explain in short how do you go about implementing filters using Apache Tomcat?
Twist: - Explain step by step of how to implement filters?
what’s the difference between Authentication and authorization?
Explain in brief the directory structure of a web application?
Can you explain JSP page life cycle?
What is EL?
how does EL search for an attribute?
What are the implicit EL objects in JSP?
How can we disable EL?
what is JSTL?
Can you explain in short what the different types of JSTL tags are?
How can we use beans in JSP?
What is tag for ?
What are JSP directives?
what are Page directives?
what are include directives?
Can you explain taglib directives?
How does JSP engines instantiate tag handler classes instances?
what’s the difference between JavaBeans and taglib directives?
what are the different scopes an object can have in a JSP page?
what are different implicit objects of JSP?
what are different Authentication Options available in servlets?
Can you explain how do we practically implement security on a resource?
How do we practically implement form based authentication?
How do we authenticate using JDBC?
Can you explain JDBCRealm?
Can you explain how do you configure JNDIRealm?
How did you implement caching in JSP?
EJB
What is EJB?
what are the different kind of EJB’s?
you are designing architecture for a project how do you decide whether you should use
session, entity or message driven bean?
Can you explain “EJBHome” and “EJBObject” in EJB?
Can client directly create object of session or entity beans?
Can you explain the concept of local interfaces?
What are the limitations of using Local object?
Which application server have you used for EJB ?
Can you explain step by step practically developing and deploying EJB component?
what is Passivation and Activation in EJB?
Can beans who are involved in transaction have “Passivation” process?
How does the server decide which beans to passivate and activate?
In what format is the conversational data written to the disk?
Can you explain in brief Life cycle for Stateless and Stateful beans?
Struts
What’s MVC pattern?
Define struts?
Can you explain the directory structure for a struts folder in brief ?
Can you give an overview of how a struts application flows?
Twist: - What are action and action form classes in Struts?
XML and WebServices
What is XML?
What is the version information in XML?
What is ROOT element in XML?
If XML does not have closing tag will it work?
Is XML case sensitive?
What is the difference between XML and HTML?
Is XML meant to replace HTML?
Can you explain why your project needed XML?
What is DTD (Document Type definition)?
What is well formed XML?
What is a valid XML?
What is CDATA section in XML?
What is CSS?
What is XSL?
What is element and attributes in XML?
What are the standard ways of parsing XML document?
In What scenarios will you use a DOM parser and SAX parser?
What is XSLT?
Define XPATH?
What is the concept of XPOINTER?
What is a Web Service ?
What is DISCO ?
What is SOAP ?
What is WSDL ?
Can you explain UDDI ?
Can you explain JAXP ?
What is a XML registry?
What is JAXR?
What is JAXM?
Can you explain how JAXM messaging model works?
Can you explain JAX-RPC?
Internationalization
Can you explain i18n and l10n?
Can you explain internationalization and localization?
What is Locale?
How do we display numbers, currency and Dates according to proper Locale format?
what are resource bundles?
How do we load a resource bundle file?
How can we do inheritance in resource bundles?
JNI
What is Native Interface in JAVA?
Can you say in brief steps required to implement Native interfaces in Java?
Can JNI be used for VB6, C# or VB.NET directly?
What are JNI functions and pointers?
How does the garbage collector know JNI objects are no more used?
Twist: - What are the different types of references JNI supports?
Twist: - How to do you delete global objects?
how does the native language C or C++ understand data types in JAVA?
Can you explain exception handling in JNI?
What are limitations for “JNIEnv” pointer in multi-threading scenarios?
What are the advantages and disadvantages of using “JNI”?
Architecture
What are design patterns ?
What is the difference between Factory and Abstract Factory Patterns?
What is MVC pattern?
Twist: - How can you implement MVC pattern in Servlets and JSP?
How can we implement singleton pattern in JAVA?
How do you implement prototype pattern in JAVA?
Twist: - How to implement cloning in JAVA? What is shallow copy and deep copy ?
Can you give a practical implementation of FAÇADE patterns?
How can we implement observer pattern in JAVA?
What is three tier architecture?
What is Service Oriented architecture?
What is aspect oriented programming?
Project Management
What is project management?
Is spending in IT projects constant through out the project?
Who is a stakeholder ?
Can you explain project life cycle ?
Twist :- How many phases are there in software project ?
Are risk constant through out the project ?
Can you explain different software development life cycles ?
What is triple constraint triangle in project management ?
What is a project baselines ?
What is effort variance?
How is normally a project management plan document organized ?
How do you estimate a project?
What is CAR (Causal Analysis and Resolution)?
What is DAR (Decision Analysis and Resolution) ?
What is a fish bone diagram ?
Twist:- What is Ishikawa diagram ?
What is pareto principle ?
Twist :- What is 80/20 principle ?
How do you handle change request?
What is internal change request?
What is difference between SITP and UTP in testing ?
What is the software you have used for project management?
What are the metrics followed in project management?
Twist: - What metrics will you look at in order to see the project is moving successfully?
You have people in your team who do not meet there deadlines or do not perform what
are the actions you will take ?
Twist :- Two of your resources have conflicts between them how would you sort it out ?
What is black box testing and White box testing?
What’s the difference between Unit testing, Assembly testing and Regression testing?
What is V model in testing?
How do you start a project?
How did you do resource allocations?
How will you do code reviews ?
What is CMMI?
What are the five levels in CMMI?
What is continuous and staged representation?
Can you explain the process areas?
What is SIX sigma?
What is DMAIC and DMADV ?
What are the various roles in Six Sigma implementation?
What are function points?
Twist: - Define Elementary process in FPA?
What are the different types of elementary process in FPA?
What are the different elements in Functions points?
Can you explain in GSC and VAF in function points?
What are unadjusted function points and how is it calculated?
Can you explain steps in function points?
What is the FP per day in your current company?
Twist :- What is your company’s productivity factor ?
Do you know Use Case points?
What is COCOMO I, COCOMOII and COCOMOIII?
What is SMC approach of estimation?
How do you estimate maintenance project and change requests?
UML
What is UML?
How many types of diagrams are there in UML ?
Twist :- Explain in short all types of diagrams in UML ?
What are advantages of using UML?
Twist: - What is Modeling and why UML ?
What is the sequence of UML diagrams in project?
Twist: - How did you implement UML in your project?
Just a small Twist: - Do I need all UML diagrams in a project?
Give a small brief explanation of all Elements in activity diagrams?
Explain Different elements of a collaboration diagram ?
Explain Component diagrams ?
Explain all parts of a deployment diagram?
Describe the various components in sequence diagrams?
What are the element in State Chart diagrams ?
Describe different elements in Static Chart diagrams ?
Explain the different elements of a Use Case ?
Twist: - What is the difference between Activity and sequence diagrams?(I leave this to
the readers)

Sunday, August 19, 2007

Database

What is RDBMS?

Relational Data Base Management Systems (RDBMS) are database management systems that maintain data records and indices in tables. Relationships may be created and maintained across and among the data and tables. In a relational database, relationships between data items are expressed by means of tables. Interdependencies among these tables are expressed by data values rather than by pointers.
This allows a high degree of data independence. An RDBMS has the capability to recombine the data items from different files, providing powerful tools for data usage.

What is normalization?

Database normalization is a data design and organization process applied to data structures based on rules that help build relational databases. In relational database design, the process of organizing data to minimize redundancy. Normalization usually involves dividing a database into two or more tables and defining relationships between the tables. The objective is to isolate data so that additions, deletions, and modifications of a field can be made in just one table and then propagated through the rest of the database via the defined relationships.

What are different normalization forms?
1NF: Eliminate Repeating Groups
Make a separate table for each set of related attributes, and give each table a primary key. Each field contains at most one value from its attribute domain.
2NF: Eliminate Redundant Data
If an attribute depends on only part of a multi-valued key, remove it to a separate table.
3NF: Eliminate Columns Not Dependent On Key
If attributes do not contribute to a description of the key, remove them to a separate table. All attributes must be directly dependent on the primary key
BCNF: Boyce-Codd Normal Form
If there are non-trivial dependencies between candidate key attributes, separate them out into distinct tables.
4NF: Isolate Independent Multiple Relationships
No table may contain two or more 1:n or n:m relationships that are not directly related.
5NF: Isolate Semantically Related Multiple Relationships
There may be practical constrains on information that justify separating logically related many-to-many relationships.
ONF: Optimal Normal Form
A model limited to only simple (elemental) facts, as expressed in Object Role Model notation.
DKNF: Domain-Key Normal Form A model free from all modification anomalies.
Remember, these normalization guidelines are cumulative. For a database to be in 3NF, it must first fulfill all the criteria of a 2NF and 1NF database.
What is Stored Procedure?
A stored procedure is a named group of SQL statements that have been previously created and stored in the server database. Stored procedures accept input parameters so that a single procedure can be used over the network by several clients using different input data. And when the procedure is
modified, all clients automatically get the new version. Stored procedures reduce network traffic and improve performance. Stored procedures can be used to help ensure the integrity of the database.
e.g. sp_helpdb, sp_renamedb, sp_depends etc.

What is Trigger?
A trigger is a SQL procedure that initiates an action when an event (INSERT, DELETE or UPDATE) occurs. Triggers are stored in and managed by the DBMS.Triggers are used to maintain the referential integrity of data by changing the data in a systematic fashion. A trigger cannot be called or executed;
the DBMS automatically fires the trigger as a result of a data modification to the associated table.
Triggers can be viewed as similar to stored procedures in that both consist of procedural logic that is stored at the database level. Stored procedures, however, are not event-drive and are not attached to a
specific table as triggers are. Stored procedures are explicitly executed by invoking a CALL to the procedure while triggers are implicitly executed. In addition, triggers can also execute stored procedures.
Nested Trigger: A trigger can also contain INSERT, UPDATE and DELETE logic within itself, so when the trigger is fired because of data modification it can also cause another data modification, thereby firing another trigger. A trigger that contains data modification logic within itself is called a nested trigger.

What is View?
A simple view can be thought of as a subset of a table. It can be used for retrieving data, as well as updating or deleting rows. Rows updated or deleted in the view are updated or deleted in the table the view was created with. It should also be noted that as data in the original table changes, so does data in the view, as views are the way to look at part of the original table. The results of using a view are not permanently stored in the database. The data accessed through a view is actually constructed using standard T-SQL select command and can come from one to many different base tables or even other views.

What is Index?
An index is a physical structure containing pointers to the data. Indices are created in an existing table to locate rows more quickly and efficiently. It is possible to create an index on one or more columns of a table, and each index is given a name. The users cannot see the indexes, they are just used to speed up queries. Effective indexes are one of the best ways to improve performance in a database application. A table scan happens when there is no index available to help a query. In a table scan SQL Server examines every row in the table to satisfy the query results. Table scans are sometimes unavoidable, but on large tables, scans have a terrific impact on performance.
Clustered indexes define the physical sorting of a database table’s rows in the storage media. For this reason, each database table may have only one clustered index.
Non-clustered indexes are created outside of the database table and contain a sorted list of references to the table itself.

What is the difference between clustered and a non-clustered index?
A clustered index is a special type of index that reorders the way records in the table are physically stored. Therefore table can have only one clustered index. The leaf nodes of a clustered index contain the data pages.
A nonclustered index is a special type of index in which the logical order of the index does not match the physical stored order of the rows on disk. The leaf node of a nonclustered index does not consist of the data pages. Instead, the leaf nodes contain index rows.

What are the different index configurations a table can have?
A table can have one of the following index configurations:
No indexes
A clustered index
A clustered index and many nonclustered indexes
A nonclustered index
Many nonclustered indexes

What is cursors?
Cursor is a database object used by applications to manipulate data in a set on a row-by-row basis,
instead of the typical SQL commands that operate on all the rows in the set at one time.
In order to work with a cursor we need to perform some steps in the following order:
Declare cursor
Open cursor
Fetch row from the cursor
Process fetched row
Close cursor
Deallocate cursor

What is the use of DBCC commands?
DBCC stands for database consistency checker. We use these commands to check the consistency of the databases, i.e., maintenance, validation task and status checks. E.g. DBCC CHECKDB - Ensures that tables in the db and the indexes are correctly linked.
DBCC CHECKALLOC - To check that all pages in a db are correctly allocated.
DBCC CHECKFILEGROUP - Checks all tables file group for any damage.

What is a Linked Server?
Linked Servers is a concept in SQL Server by which we can add other SQL Server to a Group and query both the SQL Server dbs using T-SQL Statements. With a linked server, you can create very clean, easy to follow, SQL statements that allow remote data to be retrieved, joined and combined with local data.
Storped Procedure sp_addlinkedserver, sp_addlinkedsrvlogin will be used add new Linked Server.

What is Collation?
Collation refers to a set of rules that determine how data is sorted and compared. Character data is sorted using rules that define the correct character sequence, with options for specifying casesensitivity, accent marks, kana character types and character width.

What are different type of Collation Sensitivity?
Case sensitivity
A and a, B and b, etc.
Accent sensitivity
a and á, o and ó, etc.
Kana Sensitivity
When Japanese kana characters Hiragana and Katakana are treated differently, it is called Kana sensitive.
Width sensitivity
When a single-byte character (half-width) and the same character when represented as a double-byte character (full-width) are treated differently then it is width sensitive.

What's the difference between a primary key and a unique key?
Both primary key and unique enforce uniqueness of the column on which they are defined. But by default primary key creates a clustered index on the column, where are unique creates a nonclustered index by default. Another major difference is that, primary key doesn't allow NULLs, but unique key allows one NULL only.

How to implement one-to-one, one-to-many and many-to-many relationships while designing tables?
One-to-One relationship can be implemented as a single table and rarely as two tables with primary and foreign key relationships.
One-to-Many relationships are implemented by splitting the data into two tables with primary key and foreign key relationships.
Many-to-Many relationships are implemented using a junction table with the keys from both the tables forming the composite primary key of the junction table.

What is a NOLOCK?
Using the NOLOCK query optimizer hint is generally considered good practice in order to improve concurrency on a busy system. When the NOLOCK hint is included in a SELECT statement, no locks are taken when data is read. The result is a Dirty Read, which means that another process could be updating the data at the exact time you are reading it. There are no guarantees that your query will retrieve the most recent data. The advantage to performance is that your reading of data will not block updates from taking place, and updates will not block your reading of data. SELECT statements take Shared (Read) locks. This means that multiple SELECT statements are allowed simultaneous access, but other processes are blocked from modifying the data. The updates will queue until all the reads have completed, and reads requested after the update will wait for the updates to complete. The result to
your system is delay(blocking).

What is difference between DELETE & TRUNCATE commands?
Delete command removes the rows from a table based on the condition that we provide with a WHERE clause. Truncate will actually remove all the rows from a table and there will be no data in the table after we run the truncate command.

TRUNCATE
TRUNCATE is faster and uses fewer system and transaction log resources than DELETE.
TRUNCATE removes the data by deallocating the data pages used to store the table’s data, and only the page deallocations are recorded in the transaction log.
TRUNCATE removes all rows from a table, but the table structure and its columns, constraints, indexes
and so on remain. The counter used by an identity for new rows is reset to the seed for the column.
You cannot use TRUNCATE TABLE on a table referenced by a FOREIGN KEY constraint.
Because TRUNCATE TABLE is not logged, it cannot activate a trigger.
TRUNCATE can not be Rolled back.
TRUNCATE is DDL Command.
TRUNCATE Resets identity of the table.
DELETE
DELETE removes rows one at a time and records an entry in the transaction log for each deleted row.
If you want to retain the identity counter, use DELETE instead. If you want to remove table definition
and its data, use the DROP TABLE statement.
DELETE Can be used with or without a WHERE clause
DELETE Activates Triggers.
DELETE Can be Rolled back.
DELETE is DML Command.
DELETE does not reset identity of the table.
Difference between Function and Stored Procedure?
UDF can be used in the SQL statements anywhere in the WHERE/HAVING/SELECT section where as Stored procedures cannot be.
UDFs that return tables can be treated as another rowset. This can be used in JOINs with other tables.
Inline UDF's can be though of as views that take parameters and can be used in JOINs and other Rowset operations.
When is the use of UPDATE_STATISTICS command?
This command is basically used when a large processing of data has occurred. If a large amount of deletions any modification or Bulk Copy into the tables has occurred, it has to update the indexes to take these changes into account. UPDATE_STATISTICS updates the indexes on these tables
accordingly.
What types of Joins are possible with Sql Server?
Joins are used in queries to explain how different tables are related. Joins also let you select data from a table depending upon data from another table.
Types of joins: INNER JOINs, OUTER JOINs, CROSS JOINs. OUTER JOINs are further classified as LEFT OUTER JOINS, RIGHT OUTER JOINS and FULL OUTER JOINS.

What is the difference between a HAVING CLAUSE and a WHERE CLAUSE?
Specifies a search condition for a group or an aggregate. HAVING can be used only with the SELECT statement. HAVING is typically used in a GROUP BY clause. When GROUP BY is not used, HAVING behaves like a WHERE clause. Having Clause is basically used only with the GROUP BY function in a query. WHERE Clause is applied to each row before they are part of the GROUP BY function in a query.

What is sub-query? Explain properties of sub-query.
Sub-queries are often referred to as sub-selects, as they allow a SELECT statement to be executed arbitrarily within the body of another SQL statement. A sub-query is executed by enclosing it in a set of parentheses. Sub-queries are generally used to return a single row as an atomic value, though they may be used to compare values against multiple rows with the IN keyword.
A subquery is a SELECT statement that is nested within another T-SQL statement. A subquery SELECT statement if executed independently of the T-SQL statement, in which it is nested, will return a result set. Meaning a subquery SELECT statement can standalone and is not depended on the statement in which it is nested. A subquery SELECT statement can return any number of values, and can be found in, the column list of a SELECT statement, a FROM, GROUP BY, HAVING, and/or ORDER BY clauses of a T-SQL statement. A Subquery can also be used as a parameter to a function call. Basically a subquery can be used anywhere an expression can be used.

Properties of Sub-Query
A subquery must be enclosed in the parenthesis.
A subquery must be put in the right hand of the comparison operator, and
A subquery cannot contain a ORDER-BY clause.
A query can contain more than one sub-queries.
What are types of sub-queries?
Single-row subquery, where the subquery returns only one row.
Multiple-row subquery, where the subquery returns multiple rows,.and
Multiple column subquery, where the subquery returns multiple columns.

What is SQL Profiler?
SQL Profiler is a graphical tool that allows system administrators to monitor events in an instance of Microsoft SQL Server. You can capture and save data about each event to a file or SQL Server table to analyze later. For example, you can monitor a production environment to see which stored procedures are hampering performance by executing too slowly.
Use SQL Profiler to monitor only the events in which you are interested. If traces are becoming too large, you can filter them based on the information you want, so that only a subset of the event data is collected. Monitoring too many events adds overhead to the server and the monitoring process and can cause the trace file or trace table to grow very large, especially when the monitoring process takes place over a long period of time.

What is User Defined Functions?
User-Defined Functions allow to define its own T-SQL functions that can accept 0 or more parameters and return a single scalar data value or a table data type.
What kind of User-Defined Functions can be created?
There are three types of User-Defined functions in SQL Server 2000 and they are Scalar, Inline Table-
Valued and Multi-statement Table-valued.
Scalar User-Defined Function
A Scalar user-defined function returns one of the scalar data types. Text, ntext, image and timestamp data types are not supported. These are the type of user-defined functions that most developers are used to in other programming languages. You pass in 0 to many parameters and you get a return value.
Inline Table-Value User-Defined Function
An Inline Table-Value user-defined function returns a table data type and is an exceptional alternative to a view as the user-defined function can pass parameters into a T-SQL select command and in essence provide us with a parameterized, non-updateable view of the underlying tables.
Multi-statement Table-Value User-Defined Function
A Multi-Statement Table-Value user-defined function returns a table and is also an exceptional alternative to a view as the function can support multiple T-SQL statements to build the final result where the view is limited to a single SELECT statement. Also, the ability to pass parameters into a TSQL select command or a group of them gives us the capability to in essence create a parameterized,
non-updateable view of the data in the underlying tables. Within the create function command you must define the table structure that is being returned. After creating this type of user-defined function,
It can be used in the FROM clause of a T-SQL command unlike the behavior found when using a stored procedure which can also return record sets.
Which TCP/IP port does SQL Server run on? How can it be changed?
SQL Server runs on port 1433. It can be changed from the Network Utility TCP/IP properties –> Port number. both on client and the server.
What are the authentication modes in SQL Server? How can it be changed?
Windows mode and mixed mode (SQL & Windows).
To change authentication mode in SQL Server click Start, Programs, Microsoft SQL Server and click SQL Enterprise Manager to run SQL Enterprise Manager from the Microsoft SQL Server program group.
Select the server then from the Tools menu select SQL Server Configuration Properties, and choose the Security page.

Where are SQL server users names and passwords are stored in sql server?
They get stored in master db in the sysxlogins table.

Which command using Query Analyzer will give you the version of SQL server and operating system?

SELECT SERVERPROPERTY('productversion'), SERVERPROPERTY ('productlevel'), SERVERPROPERTY('edition')

What is SQL server agent?
SQL Server agent plays an important role in the day-to-day tasks of a database administrator (DBA). It is often overlooked as one of the main tools for SQL Server management. Its purpose is to ease the implementation of tasks for the DBA, with its full-function scheduling engine, which allows you to schedule your own jobs and scripts.

Can a stored procedure call itself or recursive stored procedure? How many level SP nesting possible?
Yes. Because Transact-SQL supports recursion, you can write stored procedures that call themselves. Recursion can be defined as a method of problem solving wherein the solution is arrived at by repetitively applying it to subsets of the problem. A common application of recursive logic is to perform numeric computations that lend themselves to repetitive evaluation by the same processing steps.
Stored procedures are nested when one stored procedure calls another or executes managed code by referencing a CLR routine, type, or aggregate. You can nest stored procedures and managed code references up to 32 levels.

What is @@ERROR?
The @@ERROR automatic variable returns the error code of the last Transact-SQL statement. If there was no error, @@ERROR returns zero. Because @@ERROR is reset after each Transact-SQL statement,it must be saved to a variable if it is needed to process it further after checking it.

What is Raiseerror?
Stored procedures report errors to client applications via the RAISERROR command. RAISERROR doesn't change the flow of a procedure; it merely displays an error message, sets the @@ERROR automatic variable, and optionally writes the message to the SQL Server error log and the NT application event log.

What is log shipping?
Log shipping is the process of automating the backup of database and transaction log files on a production SQL server, and then restoring them onto a standby server. Enterprise Editions only supports log shipping. In log shipping the transactional log file from one server is automatically updated into the backup database on the other server. If one server fails, the other server will have the same db can be used this as the Disaster Recovery plan. The key feature of log shipping is that is will automatically backup transaction logs throughout the day and automatically restores them on the standby server at defined interval.

What is the difference between a local and a global variable?
A local temporary table exists only for the duration of a connection or, if defined inside a compound statement, for the duration of the compound statement.
A global temporary table remains in the database permanently, but the rows exist only within a given connection. When connection is closed, the data in the global temporary table disappears. However, the table definition remains with the database for access when database is opened next time.

What command do we use to rename a db?
sp_renamedb ‘oldname’ , ‘newname’
If someone is using db it will not accept sp_renmaedb. In that case first bring db to single user using sp_dboptions. Use sp_renamedb to rename database. Use sp_dboptions to bring database to multi user mode.

What is sp_configure commands and set commands?
Use sp_configure to display or change server-level settings. To change database-level settings, use ALTER DATABASE. To change settings that affect only the current user session, use the SET statement.

What are the different types of replication? Explain.
The SQL Server 2000-supported replication types are as follows:
Transactional
Snapshot
Merge
Snapshot replication distributes data exactly as it appears at a specific moment in time and does not monitor for updates to the data. Snapshot replication is best used as a method for replicating data that changes infrequently or where the most up-to-date values (low latency) are not a requirement. When synchronization occurs, the entire snapshot is generated and sent to Subscribers.
Transactional replication, an initial snapshot of data is applied at Subscribers, and then when data modifications are made at the Publisher, the individual transactions are captured and propagated to Subscribers.
Merge replication is the process of distributing data from Publisher to Subscribers, allowing the Publisher and Subscribers to make updates while connected or disconnected, and then merging the updates between sites when they are connected.

What are the OS services that the SQL Server installation adds?
MS SQL SERVER SERVICE, SQL AGENT SERVICE, DTC (Distribution transac co-ordinator)

What are three SQL keywords used to change or set someone’s permissions?
GRANT, DENY, and REVOKE.
What does it mean to have quoted_identifier on? What are the implications of having it off?
When SET QUOTED_IDENTIFIER is ON, identifiers can be delimited by double quotation marks, and literals must be delimited by single quotation marks. When SET QUOTED_IDENTIFIER is OFF, identifiers cannot be quoted and must follow all Transact-SQL rules for identifiers.

What is the STUFF function and how does it differ from the REPLACE function?
STUFF function to overwrite existing characters. Using this syntax, STUFF(string_expression, start, length, replacement_characters), string_expression is the string that will have characters substituted, start is the starting position, length is the number of characters in the string that are substituted, and replacement_characters are the new characters interjected into the string.

REPLACE function to replace existing characters of all occurance. Using this syntax
REPLACE(string_expression, search_string, replacement_string), where every incidence of search_string found in the string_expression will be replaced with replacement_string.

Using query analyzer, name 3 ways to get an accurate count of the number of records in a table?
SELECT * FROM table1
SELECT COUNT(*) FROM table1
SELECT rows FROM sysindexes WHERE id = OBJECT_ID(table1) AND indid < 2

How to rebuild Master Database?
Shutdown Microsoft SQL Server 2000, and then run Rebuildm.exe. This is located in the Program Files\Microsoft SQL Server\80\Tools\Binn directory.
In the Rebuild Master dialog box, click Browse.
In the Browse for Folder dialog box, select the \Data folder on the SQL Server 2000 compact disc or in the shared network directory from which SQL Server 2000 was installed, and then click OK.
Click Settings. In the Collation Settings dialog box, verify or change settings used for the master database and all other databases.
Initially, the default collation settings are shown, but these may not match the collation selected during setup. You can select the same settings used during setup or select new collation settings. When done,
click OK.
In the Rebuild Master dialog box, click Rebuild to start the process.
The Rebuild Master utility reinstalls the master database.
To continue, you may need to stop a server that is running.
Source: http://msdn2.microsoft.com/en-us/library/aa197950(SQL.80).aspx
What is the basic functions for master, msdb, model, tempdb databases?
The Master database holds information for all databases located on the SQL Server instance and is the glue that holds the engine together. Because SQL Server cannot start without a functioning master database, you must administer this database with care.
The msdb database stores information regarding database backups, SQL Agent information, DTS packages, SQL Server jobs, and some replication information such as for log shipping.
The tempdb holds temporary objects such as global and local temporary tables and stored procedures.
The model is essentially a template database used in the creation of any new user database created in the instance.

What are primary keys and foreign keys?
Primary keys are the unique identifiers for each row. They must contain unique values and cannot be null. Due to their importance in relational databases, Primary keys are the most fundamental of all keys and constraints. A table can have only one Primary key.
Foreign keys are both a method of ensuring data integrity and a manifestation of the relationship between tables.

What is data integrity? Explain constraints?
Data integrity is an important feature in SQL Server. When used properly, it ensures that data is accurate, correct, and valid. It also acts as a trap for otherwise undetectable bugs within applications.
A PRIMARY KEY constraint is a unique identifier for a row within a database table. Every table should have a primary key constraint to uniquely identify each row and only one primary key constraint can be created for each table. The primary key constraints are used to enforce entity integrity.
A UNIQUE constraint enforces the uniqueness of the values in a set of columns, so no duplicate values are entered. The unique key constraints are used to enforce entity integrity as the primary key constraints.
A FOREIGN KEY constraint prevents any actions that would destroy links between tables with the corresponding data values. A foreign key in one table points to a primary key in another table. Foreign keys prevent actions that would leave rows with foreign key values when there are no primary keys with that value. The foreign key constraints are used to enforce referential integrity.
A CHECK constraint is used to limit the values that can be placed in a column. The check constraints are used to enforce domain integrity.
A NOT NULL constraint enforces that the column will not accept null values. The not null constraints are used to enforce domain integrity, as the check constraints.
What are the properties of the Relational tables?
Relational tables have six properties:
Values are atomic.
Column values are of the same kind.
Each row is unique.
The sequence of columns is insignificant.
The sequence of rows is insignificant.
Each column must have a unique name.
What is De-normalization?
De-normalization is the process of attempting to optimize the performance of a database by adding redundant data. It is sometimes necessary because current DBMSs implement the relational model poorly. A true relational DBMS would allow for a fully normalized database at the logical level, while providing physical storage of data that is tuned for high performance. De-normalization is a technique to move from higher to lower normal forms of database modeling in order to speed up database access.
How to get @@error and @@rowcount at the same time?
If @@Rowcount is checked after Error checking statement then it will have 0 as the value of @@Recordcount as it would have been reset.
And if @@Recordcount is checked before the error-checking statement then @@Error would get reset.
To get @@error and @@rowcount at the same time do both in same statement and store them in local variable. SELECT @RC = @@ROWCOUNT, @ER = @@ERROR

What is Identity?
Identity (or AutoNumber) is a column that automatically generates numeric values. A start and increment value can be set, but most DBA leave these at 1. A GUID column also generates numbers, the value of this cannot be controled. Identity/GUID columns do not need to be indexed.

What is a Scheduled Jobs or What is a Scheduled Tasks?
Scheduled tasks let user automate processes that run on regular or predictable cycles. User can schedule administrative tasks, such as cube processing, to run during times of slow business activity.
User can also determine the order in which tasks run by creating job steps within a SQL Server Agent job. E.g. Back up database, Update Stats of Tables. Job steps give user control over flow of execution.
If one job fails, user can configure SQL Server Agent to continue to run the remaining tasks or to stop execution.

What is a table called, if it does not have neither Cluster nor Non-cluster Index? What is it used for?
Unindexed table or Heap. Microsoft Press Books and Book On Line (BOL) refers it as Heap.
A heap is a table that does not have a clustered index and, therefore, the pages are not linked by pointers. The IAM pages are the only structures that link the pages in a table together.
Unindexed tables are good for fast storing of data. Many times it is better to drop all indexes from table and than do bulk of inserts and to restore those indexes after that.

What is BCP? When does it used?
BulkCopy is a tool used to copy huge amount of data from tables and views. BCP does not copy the structures same as source to destination.
How do you load large data to the SQL server database?
BulkCopy is a tool used to copy huge amount of data from tables. BULK INSERT command helps to Imports a data file into a database table or view in a user-specified format.

Can we rewrite subqueries into simple select statements or with joins?
Subqueries can often be re-written to use a standard outer join, resulting in faster performance. As we may know, an outer join uses the plus sign (+) operator to tell the database to return all non-matching rows with NULL values. Hence we combine the outer join with a NULL test in the WHERE clause to reproduce the result set without using a sub-query.

Can SQL Servers linked to other servers like Oracle?
SQL Server can be lined to any server provided it has OLE-DB provider from Microsoft to allow a link.
E.g. Oracle has a OLE-DB provider for oracle that Microsoft provides to add it as linked server to SQL Server group.




How to know which index a table is using?
SELECT table_name,index_name FROM user_constraints
How to copy the tables, schema and views from one SQL server to another?
Microsoft SQL Server 2000 Data Transformation Services (DTS) is a set of graphical tools and programmable objects that lets user extract, transform, and consolidate data from disparate sources into single or multiple destinations.

What is Self Join?
This is a particular case when one table joins to itself, with one or two aliases to avoid confusion. A self join can be of any type, as long as the joined tables are the same. A self join is rather unique in that it involves a relationship with only one table. The common example is when company have a hierarchal reporting structure whereby one member of staff reports to another.

What is Cross Join?
A cross join that does not have a WHERE clause produces the Cartesian product of the tables involved in the join. The size of a Cartesian product result set is the number of rows in the first table multiplied by the number of rows in the second table. The common example is when company wants to combine
each product with a pricing table to analyze each product at each price.

Which virtual table does a trigger use?
Inserted and Deleted.

List few advantages of Stored Procedure.
Stored procedure can reduced network traffic and latency, boosting application performance.
Stored procedure execution plans can be reused, staying cached in SQL Server's memory,reducing server overhead.
Stored procedures help promote code reuse.
Stored procedures can encapsulate logic. You can change stored procedure code without affecting clients.
Stored procedures provide better security to your data.
What is DataWarehousing?
Subject-oriented, meaning that the data in the database is organized so that all the data elements relating to the same real-world event or object are linked together;
Time-variant, meaning that the changes to the data in the database are tracked and recorded so that reports can be produced showing changes over time;
Non-volatile, meaning that data in the database is never over-written or deleted, once committed, the data is static, read-only, but retained for future reporting;
Integrated, meaning that the database contains data from most or all of an organization's operational applications, and that this data is made consistent.
What is OLTP(OnLine Transaction Processing)?
In OLTP - online transaction processing systems relational database design use the discipline of data modeling and generally follow the Codd rules of data normalization in order to ensure absolute data integrity. Using these rules complex information is broken down into its most simple structures (a table) where all of the individual atomic level elements relate to each other and satisfy the normalization rules.
How do SQL server 2000 and XML linked? Can XML be used to access data?
FOR XML (ROW, AUTO, EXPLICIT)
You can execute SQL queries against existing relational databases to return results as XML rather than standard rowsets. These queries can be executed directly or from within stored procedures. To retrieve XML results, use the FOR XML clause of the SELECT statement and specify an XML mode of RAW, AUTO, or EXPLICIT.
OPENXML
OPENXML is a Transact-SQL keyword that provides a relational/rowset view over an in-memory XML document. OPENXML is a rowset provider similar to a table or a view. OPENXML provides a way to access XML data within the Transact-SQL context by transferring data from an XML document into the relational tables. Thus, OPENXML allows you to manage an XML document and its interaction with the
relational environment.

What is an execution plan? When would you use it? How would you view the execution plan?
An execution plan is basically a road map that graphically or textually shows the data retrieval methods chosen by the SQL Server query optimizer for a stored procedure or ad-hoc query and is a very useful tool for a developer to understand the performance characteristics of a query or stored procedure since the plan is the one that SQL Server will place in its cache and use to execute the stored procedure or
query. From within Query Analyzer is an option called "Show Execution Plan" (located on the Query drop-down menu). If this option is turned on it will display query execution plan in separate window when query is ran again.