Dedicated Administrator Connection [DAC] in SQL Server


DAC [Dedicated Administrator Connection ] is feature added from SQL Server 2005 version . Database administrator use this fetaure to connect to a SQL Server instance When the database engine not responding to the regular connection so the database administrator use this fetaure to connect to the instance to solve the problem Instead of rebooting  the SQL Server.

By Defult this feature is disable in All SQL Server version From 2005 to the New version 2012.

Note :  your SQL Server browser must be Runing

enable the DAC using below T-SQL command

Use master


sp_configure ‘show advanced options’ , 1


sp_configure ‘remote admin connections’, 1



enable the DAC using SSMS

1- write click on your SQL Server Probirties >> Factes >>  Service Area Configuration >> RemoteDacEnabled

Change it from False To True

Now try to connect by write ADMN: before your instance name like this


then your User name and your password or connect windows Authentication but if you try to connect by the default way SQL Server will give you this Error

Dedicated administrator connections are not supported. (ObjectExplorer)


So if you want to connect with this Feature you must make this steps

Go to File >>> New >>> Database Engine Query >>>> Admin:InstanceName

 then your Session will open

Note : You can not open 2 Session

Using DBCC UPDATEUSAGE to correct inaccuracies(Copy from another blog)

The DBCC command can be run on a database to correct inaccuracies of all objects in that database or you can also correct the inaccuracies of a single table by including that table name. If you would like to run the command for a particular database, then you can run the following command


You can also run the below command to correct the inaccuracies for the current database


Remarks : I take this Information Copy from this Blog :

Change The Server Collation after installation

After you finish installation for SQL server may be you want to change the Server collation or database Collation so leat’s see what will we do if we want to make this :

1- if you want to know what’s your database collation know

SELECT name, collation_name

FROM sys.databases WHERE name = ‘test’   — put your database name here

2- If you want to get a list of all available collations on the server using

SELECT * FROM ::fn_helpcollations()

3- Alter Database Collation

ALTER DATABASE test           — put your database name here

COLLATE Arabic_CI_AS        — replace with whatever collation you need

4- IF you want to know what’s your server collation


Enable xp_cmdshell using sp_configure

—- To allow advanced options to be changed.

EXEC sp_configure ‘show advanced options’, 1


—- To update the currently configured value for advanced options.



—- To enable the feature.

EXEC sp_configure ‘xp_cmdshell’, 1


—- To update the currently configured value for this feature.