Move a database using detach and attach (Transact-SQL)

Applies to: SQL Server

This topic describes how to move a detached database to another location and re-attach it to the same or a different server instance in SQL Server. However, we recommend that you move databases by using the ALTER DATABASE planned relocation procedure, instead of using detach and attach. For more information, see Move User Databases.


We recommend that you do not attach or restore databases from unknown or untrusted sources. Such databases could contain malicious code that might execute unintended Transact-SQL code or cause errors by modifying the schema or the physical database structure. Before you use a database from an unknown or untrusted source, run DBCC CHECKDB on the database on a nonproduction server and also examine the code, such as stored procedures or other user-defined code, in the database.


To move a database by using detach and attach

  1. Detach the database. For more information, see Detach a Database.

  2. In a Windows Explorer or Windows Command Prompt window, move the detached database file or files and log file or files to the new location.

    You should move the log files even if you intend to create new log files. In some cases, reattaching a database requires its existing log files. Therefore, always keep all the detached log files until the database has been successfully attached without them.


    If you try to attach the database without specifying the log file, the attach operation will look for the log file in its original location. If a copy of the log still exists in the original location, that copy is attached. To avoid using the original log file, either specify the path of the new log file or remove the original copy of the log file (after copying it to the new location).

  3. Attach the copied files. For more information, see Attach a Database.


The following example creates a copy of the AdventureWorks2022 database named MyAdventureWorks. The Transact-SQL statements are executed in a Query Editor window that is connected to the server instance to which is attached.

  1. Detach the AdventureWorks2022 database by executing the following Transact-SQL statements:

    USE master;  
    EXEC sp_detach_db @dbname = N'AdventureWorks2022';  
  2. Using the method of your choice, copy the database files (AdventureWorks208R2_Data.mdf and AdventureWorks208R2_log) to: C:\MySQLServer\AdventureWorks208R2_Data.mdf and C:\MySQLServer\AdventureWorks208R2_Log.ldf, respectively.


    For a production database, place the database and transaction log on separate disks.

    To copy files over the network to a disk on a remote computer, use the universal naming convention (UNC) name of the remote location. A UNC name takes the form \\Servername\Sharename\Path\Filename. As with writing files to the local hard disk, the appropriate permissions that are required to read or write to a file on the remote disk must be granted to the user account used by the instance of SQL Server.

  3. Attach the moved database and, optionally, its log by executing the following Transact-SQL statements:

    USE master;  
    CREATE DATABASE MyAdventureWorks   
        ON (FILENAME = 'C:\MySQLServer\AdventureWorks2022_Data.mdf'),  
        (FILENAME = 'C:\MySQLServer\AdventureWorks2022_Log.ldf')  
        FOR ATTACH;  

    In SQL Server Management Studio, a newly attached database is not immediately visible in Object Explorer. To view the database, in Object Explorer, click View, and then Refresh. When the Databases node is expanded in Object Explorer, the newly attached database now appears in the list of databases.

See Also

Database Detach and Attach (SQL Server)