MS SQL Tips

Here are some MS SQL Tips, Tricks, Recipes, etc.:

• Find out who's using what databases:

1. Open SQL Query Analyzer
2. type "exec sp_who" into the Query window.
3. Click "Execute Query" or press F5.

• From cryptosid at experts-exchange:
• before using DBCC REBUILD_LOG better check this article and read it through
  http://www.sqlmag.com/Articles/Index.cfm?ArticleID=9011
  
  a safe alternative would be
  Backup the consistent Database.
  and RESTORE the database with the MOVE option using which u can move the database files to whichever drive u want...

• Get information on a DB's logfile:

1. Open Query Analyzer
2. Type this in the query window, then click Execute Query:
• use db_name
• dbcc LOGINFO

• Detach and re-attach a database:
1. confirm that nothing has the db open. Open QA and run "exec sp_who"
2. If nobody is using the db, detach the database with the QA command "EXEC sp_detach_db 'db_name' ", or right-click the DB in the enterprise mgr and select "detach database".
   
3. Re-attach the DB by using the QA command "EXEC sp_attach_db 'db_name', 'x:\full\path\to\db\file\db_filename.MDF' " or by right-clicking the databases in the enterprise mgr, and select "attach database".
   

• How to set up SQL mail
• http://support.microsoft.com/?id=263556

• Safely delete a transaction log:

1. make sure nobody's using the database, as above under "Detach..."
2. Backup the database.
3. make sure nobody's using the database still.
4. detach the database, as above.
5. rename the log file (.LDF file)
6. re-attach the database, as above.
7. logfile should be automatically re-created.

• From rsrm at experts-exchange, http://www.experts-exchange.com/Databases/Microsoft_SQL_Server/Q_20823435.html

• Comment from rsrsm Date: 12/11/2003 07:29PM PST	Comment
  If the log file is deleted for the database and SQL server is not able to locate it..you can rebuild the log. try the following steps (But if the log file is not deleted then you can ignore this comment): REBUILD LOG and recover a suspect database: 1. Back up the .mdf/.ndf and .ldf files. 2. Change the database context to Master and allow updates to system tables: Use Master Go sp_configure 'allow updates', 1 reconfigure with override Go 3. Set the database in Emergency (bypass recovery) mode: select * from sysdatabases where name = '' -- note the value of the status column for later use begin tran update sysdatabases set status = 32768 where name = '' -- Verify one row is updated before committing commit tran If you run DBCC REBUILD_LOG without setting the database in Emergency mode, the command does not work. You do not receive an error, but the log is not rebuilt either. 4. Stop and restart SQL server. If you run DBCC REBUILD_LOG without recycling the server, the following message displays: Server: Msg 5023, Level 16, State 2, Line 1 Database must be put in bypass recovery mode to rebuild the log. DBCC execution completed. If DBCC printed error messages, contact your system administrator. 5. The syntax for DBCC REBUILD_LOG is as follows: DBCC REBUILD_LOG('','') where is the name of the database and is the physical path to the new log file, not a logical file name. If you do not specify the full path, the new log is created in the Windows NT system root directory (by default, this is the Winnt\System32 directory). If the file is placed in the Winnt\System32 folder, you can move it to a different folder by running the following commands from the SQL Query Analyzer: sp_detach_db '' Go Move the log file over from the Winnt\System32 folder to the preferred folder. sp_attach_db '', '', '' Go If a log file with the same name as specified in DBCC REBUILD_LOG already exists in that directory, then the following message occurs: Server: Msg 5025, Level 16, State 1, Line 1 The file 'C:\MSSQL7\Data\' already exists. It should be renamed or deleted so that a new log file can be created. DBCC execution completed. If DBCC printed error messages, contact your system administrator. You will need to specify a different filename or rename or delete the existing one. Rebuild the log with this code: DBCC TRACEON (3604) DBCC REBUILD_LOG('','') Go If the command is successful, the following message appears: Warning: The log for database '' has been rebuilt. Transactional consistency has been lost. DBCC CHECKDB should be run to validate physical consistency. Database options will have to be reset, and extra log files may need to be deleted. After the log is successfully rebuilt, the database is placed in DBO Use Only mode. That is, the status of the database is 2048 irrespective of what the status was previously. You must reset the status using sp_dboption or through the SEM. 6. Set the database in single-user mode and run DBCC CHECKDB to validate physical consistency: sp_dboption '', 'single user', 'true' DBCC CHECKDB('') Go begin tran update sysdatabases set status = where name = '' -- verify one row is updated before committing commit tran Go 7. Turn off the updates to system tables by using: sp_configure 'allow updates', 0 reconfigure with override Go WARNING: After verifying the consistency of the database by running DBCC CHECKDB, and fixing any errors, please make sure to check the database for logical consistency as well. Because a new log has been built, the transactions in the old log are lost, hence you must also verify the logical consistency of the data as well.