Saturday, March 29, 2008

FAQ - Database Testing (101 to 110)

101. 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.

102. 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

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

103. What is SQL server agent?

SQL Server agent plays an important role in the day-to-day tasks of a database dministrator (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.

104. 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.

105. 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.

106. What is Raise error?

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.

107. 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.

108. 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.

109. 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.

110. 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.

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