Italian (IT)

Migrate Ms SQL Server Databases

Sometimes we have to migrate the contents of a Ms SQL instance from one server to another.
Often we don't know the credentials of the single databases to be migrated.
Sometimes we need to create a second server, in line with the original, and change at the last minute the server name and instance name to make it identical to the previous.
Using some scripts we can easily make this.

We need to connect with SQL Management Studio to the instance to be migrated with sa user.
Clean up the database log before starting migration operations.

USE [myDbName]
GO
DBCC SHRINKDATABASE (N'myDbName' )
GO
DBCC SHRINKFILE (N'myDbName' , 0 , TRUNCATEONLY )
GO
DBCC SHRINKFILE (N'myDbName_log' , 0 , TRUNCATEONLY )
GO
    

Sometimes the size of the database log file isn't reduced. In this case, we can force it with this command:

USE [myDbName]
GO
ALTER DATABASE [myDbName]
SET RECOVERY SIMPLE;
GO
DBCC SHRINKFILE( 2, 200 )
    

We backup all instance databases using this script:

DECLARE @name VARCHAR(50) -- database name  
DECLARE @path VARCHAR(256) -- path for backup files  
DECLARE @fileName VARCHAR(256) -- filename for backup  
DECLARE @fileDate VARCHAR(20) -- used for file name
 
-- Specify database backup directory
SET @path = 'C:\Backup\'  
 
-- Specify filename format
SELECT @fileDate = CONVERT(VARCHAR(20),GETDATE(),112) 
 
DECLARE db_cursor CURSOR FOR  
SELECT name 
FROM master.dbo.sysdatabases 
WHERE name NOT IN ('master','model','msdb','tempdb')  -- Exclude these databases
 
OPEN db_cursor   
FETCH NEXT FROM db_cursor INTO @name   
 
WHILE @@FETCH_STATUS = 0   
BEGIN   
  SET @fileName = @path + @name + '_' + @fileDate + '.BAK'  
  BACKUP DATABASE @name TO DISK = @fileName  
 
  FETCH NEXT FROM db_cursor INTO @name   
END
 
CLOSE db_cursor   
DEALLOCATE db_cursor
    

You cannot extract the passwords of login users.
But we can export their hash in a script.
Using this, we can put them on the new server, so that they work exactly like in the old instance.

IF OBJECT_ID ('sp_hexadecimal') IS NOT NULL
  DROP PROCEDURE sp_hexadecimal
GO
CREATE PROCEDURE sp_hexadecimal
  @binvalue varbinary(256),
  @hexvalue varchar (514) OUTPUT
AS
DECLARE @charvalue varchar (514)
DECLARE @i int
DECLARE @length int
DECLARE @hexstring char(16)
SELECT @charvalue = '0x'
SELECT @i = 1
SELECT @length = DATALENGTH (@binvalue)
SELECT @hexstring = '0123456789ABCDEF'
WHILE (@i <= @length)
BEGIN
  DECLARE @tempint int
  DECLARE @firstint int
  DECLARE @secondint int
  SELECT @tempint = CONVERT(int, SUBSTRING(@binvalue,@i,1))
  SELECT @firstint = FLOOR(@tempint/16)
  SELECT @secondint = @tempint - (@firstint*16)
  SELECT @charvalue = @charvalue +
    SUBSTRING(@hexstring, @firstint+1, 1) +
    SUBSTRING(@hexstring, @secondint+1, 1)
  SELECT @i = @i + 1
END

SELECT @hexvalue = @charvalue
GO

IF OBJECT_ID ('sp_export_login') IS NOT NULL
  DROP PROCEDURE sp_export_login
GO
CREATE PROCEDURE sp_export_login @login_name sysname = NULL AS
DECLARE @name sysname
DECLARE @type varchar (1)
DECLARE @hasaccess int
DECLARE @denylogin int
DECLARE @is_disabled int
DECLARE @PWD_varbinary  varbinary (256)
DECLARE @PWD_string  varchar (514)
DECLARE @SID_varbinary varbinary (85)
DECLARE @SID_string varchar (514)
DECLARE @tmpstr  varchar (1024)
DECLARE @is_policy_checked varchar (3)
DECLARE @is_expiration_checked varchar (3)
DECLARE @defaultdb sysname

IF (@login_name IS NULL)
  DECLARE login_curs CURSOR FOR
  SELECT p.sid, p.name, p.type, p.is_disabled, p.default_database_name, l.hasaccess, l.denylogin FROM
  sys.server_principals p LEFT JOIN sys.syslogins l
    ON ( l.name = p.name ) WHERE p.type IN ( 'S', 'G', 'U' ) AND p.name <> 'sa'
ELSE
  DECLARE login_curs CURSOR FOR
    SELECT p.sid, p.name, p.type, p.is_disabled, p.default_database_name, l.hasaccess, l.denylogin FROM
    sys.server_principals p LEFT JOIN sys.syslogins l
      ON ( l.name = p.name ) WHERE p.type IN ( 'S', 'G', 'U' ) AND p.name = @login_name
OPEN login_curs

FETCH NEXT FROM login_curs INTO @SID_varbinary, @name, @type, @is_disabled, @defaultdb, @hasaccess, @denylogin
IF (@@fetch_status = -1)
BEGIN
  PRINT 'No login(s) found.'
  CLOSE login_curs
  DEALLOCATE login_curs
  RETURN -1
END
SET @tmpstr = '/* sp_export_login script '
PRINT @tmpstr
SET @tmpstr = '** Generated ' + CONVERT (varchar, GETDATE()) + ' on ' + @@SERVERNAME + ' */'
PRINT @tmpstr
PRINT ''
WHILE (@@fetch_status <> -1)
BEGIN
  IF (@@fetch_status <> -2)
  BEGIN
    PRINT ''
    SET @tmpstr = '-- Login: ' + @name
    PRINT @tmpstr
    IF (@type IN ( 'G', 'U'))
    BEGIN -- NT authenticated account/group
      SET @tmpstr = 'CREATE LOGIN ' + QUOTENAME( @name ) + ' FROM WINDOWS WITH DEFAULT_DATABASE = [' + @defaultdb + ']'
    END
    ELSE BEGIN -- SQL Server authentication
      -- obtain password and sid
        SET @PWD_varbinary = CAST( LOGINPROPERTY( @name, 'PasswordHash' ) AS varbinary (256) )
        EXEC sp_hexadecimal @PWD_varbinary, @PWD_string OUT
        EXEC sp_hexadecimal @SID_varbinary,@SID_string OUT

        -- obtain password policy state
        SELECT @is_policy_checked = CASE is_policy_checked WHEN 1 THEN 'ON' WHEN 0 THEN 'OFF' ELSE NULL END FROM sys.sql_logins WHERE name = @name
        SELECT @is_expiration_checked = CASE is_expiration_checked WHEN 1 THEN 'ON' WHEN 0 THEN 'OFF' ELSE NULL END FROM sys.sql_logins WHERE name = @name

        SET @tmpstr = 'CREATE LOGIN ' + QUOTENAME( @name ) + ' WITH PASSWORD = ' + @PWD_string + ' HASHED, SID = ' + @SID_string + ', DEFAULT_DATABASE = [' + @defaultdb + ']'

        IF ( @is_policy_checked IS NOT NULL )
        BEGIN
          SET @tmpstr = @tmpstr + ', CHECK_POLICY = ' + @is_policy_checked
        END
        IF ( @is_expiration_checked IS NOT NULL )
        BEGIN
          SET @tmpstr = @tmpstr + ', CHECK_EXPIRATION = ' + @is_expiration_checked
        END
    END
    IF (@denylogin = 1)
    BEGIN -- login is denied access
      SET @tmpstr = @tmpstr + '; DENY CONNECT SQL TO ' + QUOTENAME( @name )
    END
    ELSE IF (@hasaccess = 0)
    BEGIN -- login exists but does not have access
      SET @tmpstr = @tmpstr + '; REVOKE CONNECT SQL TO ' + QUOTENAME( @name )
    END
    IF (@is_disabled = 1)
    BEGIN -- login is disabled
      SET @tmpstr = @tmpstr + '; ALTER LOGIN ' + QUOTENAME( @name ) + ' DISABLE'
    END
    PRINT @tmpstr
  END

  FETCH NEXT FROM login_curs INTO @SID_varbinary, @name, @type, @is_disabled, @defaultdb, @hasaccess, @denylogin
  END
CLOSE login_curs
DEALLOCATE login_curs
RETURN 0
GO
    

In the new SQL server, load the previous database backups.
Execute the script created to insert the login users.
Probably, users will be present but not connected to their databases.
They are orphan users.
With the following script we can combine again users to their databases.

SET NOCOUNT ON
USE myDbName
GO
DECLARE @loop INT
DECLARE @USER sysname
 
IF OBJECT_ID ('tempdb..#Orphaned') IS NOT NULL
  BEGIN
    DROP TABLE #orphaned
  END
 
CREATE TABLE #Orphaned (UserName sysname, UserSID VARBINARY (85), IDENT INT IDENTITY(1 ,1))
 
INSERT INTO #Orphaned
EXEC SP_CHANGE_USERS_LOGIN 'report';
 
IF(SELECT COUNT(*) FROM #Orphaned) > 0
BEGIN
  SET @loop = 1
  WHILE @loop <= (SELECT MAX( IDENT) FROM #Orphaned )
    BEGIN
      SET @USER = (SELECT UserName FROM #Orphaned WHERE IDENT = @loop)
      IF( SELECT COUNT (*) FROM sys. server_principals WHERE [Name] = @USER ) <= 0
        BEGIN
          EXEC SP_ADDLOGIN @USER, 'password'
        END
    
    EXEC SP_CHANGE_USERS_LOGIN 'update_one' ,@USER, @USER
    PRINT @USER + ' link to DB user reset';
    SET @loop = @loop + 1
  END
END
SET NOCOUNT OFF
    

After completing tests on migrated databases, shut down the old server and change the name and IP of the new server to take over it.
As a final activity, we must update the instance data with the new server name, using these commands:

-- Show current server name
SELECT @@SERVERNAME AS 'Server Name'
-- Delete old server name
EXEC  Sp_dropserver 'OLDSERVERNAME\SQLEXPRESS'
-- Insert new server name
EXEC  Sp_addserver 'NEWSERVERNAME\SQLEXPRESS' , 'local'
    

Finally, reboot SQL Server service.


© 2017 Bruno Tessaro. My life in the web. All right reserved.

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