还原数据库SQL Server查询

Question

I want a way to write my own query to restore the database. The database to restore needs to have all the settings to delete the current user and re-map the same user. The reason for that is because when the database is restored, the user will not have the right settings to use the database and will have to re assign the user the privileges.

Answer 1

Check this out:-

Step 1: Retrive the Logical file name of the database from backup.

RESTORE FILELISTONLY
FROM DISK = 'D:BackUpYourBaackUpFile.bak'

GO

Step 2: Use the values in the LogicalName Column in following Step. ----Make Database to single user Mode

ALTER DATABASE YourDB
SET SINGLE_USER WITH
ROLLBACK IMMEDIATE

----Restore Database

RESTORE DATABASE YourDB
FROM DISK = 'D:BackUpYourBaackUpFile.bak'
WITH MOVE 'YourMDFLogicalName' TO 'D:DataYourMDFFile.mdf',
MOVE 'YourLDFLogicalName' TO 'D:DataYourLDFFile.ldf'

/ If there is no error in statement before database will be in multiuser mode. If error occurs please execute following command it will convert database in multi user. /

ALTER DATABASE YourDB SET MULTI_USER
GO

Answer 2

The reason for that is because when the database is restored, the user will not have the right settings to use the database and will have to re assign the user the privileges.

I guess that:

1. You are using mixed mode authentication and the user is a SQL Server user (not a Windows user)
2. You are restoring the database to a different server than the one where the backup was made

Correct?

If yes, you need to consider the following:

1. The user must exist on the second server as well, it's not created automatically when you restore the database there
2. It's not enough to just create a new user with the same name on the second server - to SQL Server, this would be a different user!

I guess that the second point is the reason why your user doesn't have "the right settings" after restoring.

Some background:

• Internally, all SQL Server users are represented by a SID (something unique and unreadable - similar to a GUID . SQL Server doesn't care about the actual user name internally) .
• The permissions that each user has on a database are saved inside the database, using the SID and not the username
• When you restore the database to a different server, the permissions are restored with the database...but they only work when there's a user with the exact SID on the new server
• As I said before: when you just create a new user with the same name, he gets a new SID.

So what probably happened is this:

• on the old server, there's a user "Mohammed Tahir" with the SID 123456789
• inside the database, there's a permission that says "SID 123456789 is allowed to read from this database"
• you restored the database on the new server
• you created a user "Mohammed Tahir" on the new server, but he has a different SID (let's say 987654321 ), so the existing permissions on 123456789 don't work for him!

---

So what you need is a way to "copy" the user from the old server to the new server, with the exact same SID.

There is a stored procedure from Microsoft named sp_help_revlogin , which does just that.
It generates a script with all the users from the old server. You can then run the script on the new server, and it will create the users with the same SIDs they had on the old server.
Then, you can restore the database from the old server to the new server, and all the permissions already in the database just work .

You can get sp_help_revlogin from this MSDN article:
How to transfer logins and passwords between instances of SQL Server .

Note that there is nothing special about the actual restoring process - it's the users and their SIDs that make the difference.
So you don't need any "special" commands to restore the database, just the standard ones, for example the one from Rahul Tripathi's answer .