SQLServer数据库从高版本降级到低版本实例详解

SET QUOTED_IDENTIFIER ON 
 SET ANSI_NULLS ON 
 GO 
 create procedure sys.sp_dbcmptlevel      -- 1997/04/15 
  @dbname sysname = NULL,         -- database name to change 
  @new_cmptlevel tinyint = NULL OUTPUT  -- the new compatibility level to change to 
 as 
  set nocount  on 
  
  declare @exec_stmt nvarchar(max) 
  declare @returncode int 
  declare @comptlevel float(8) 
  declare @dbid int          -- dbid of the database 
  declare @dbsid varbinary(85)    -- id of the owner of the database 
  declare @orig_cmptlevel tinyint   -- original compatibility level 
  declare @input_cmptlevel tinyint  -- compatibility level passed in by user 
    ,@cmptlvl80 tinyint       -- compatibility to SQL Server Version 8.0 
    ,@cmptlvl90 tinyint       -- compatibility to SQL Server Version 9.0 
    ,@cmptlvl100 tinyint        -- compatibility to SQL Server Version 10.0 
  select @cmptlvl80 = 80, 
      @cmptlvl90 = 90, 
      @cmptlvl100 = 100 
  
  -- SP MUST BE CALLED AT ADHOC LEVEL -- 
  if (@@nestlevel > 1) 
  begin 
    raiserror(15432,-1,-1,'sys.sp_dbcmptlevel') 
    return (1) 
  end 
  
  -- If no @dbname given, just list the valid compatibility level values. 
  if @dbname is null 
  begin 
    raiserror (15048, -1, -1, @cmptlvl80, @cmptlvl90, @cmptlvl100) 
    return (0) 
  end 
  
  -- Verify the database name and get info 
  select @dbid = dbid, @dbsid = sid ,@orig_cmptlevel = cmptlevel 
    from master.dbo.sysdatabases 
    where name = @dbname 
  
  -- If @dbname not found, say so and list the databases. 
  if @dbid is null 
  begin 
    raiserror(15010,-1,-1,@dbname) 
    print ' ' 
    select name as 'Available databases:' 
      from master.dbo.sysdatabases 
    return (1) 
  end 
  
  -- Now save the input compatibility level and initialize the return clevel 
  -- to be the current clevel 
  select @input_cmptlevel = @new_cmptlevel 
  select @new_cmptlevel = @orig_cmptlevel 
  
  -- If no clevel was supplied, display and output current level. 
  if @input_cmptlevel is null 
  begin 
    raiserror(15054, -1, -1, @orig_cmptlevel) 
    return(0) 
  end 
  
  -- If invalid clevel given, print usage and return error code 
  -- 'usage: sp_dbcmptlevel [dbname [, compatibilitylevel]]' 
  if @input_cmptlevel not in (@cmptlvl80, @cmptlvl90, @cmptlvl100) 
  begin 
    raiserror(15416, -1, -1) 
    print ' ' 
    raiserror (15048, -1, -1, @cmptlvl80, @cmptlvl90, @cmptlvl100) 
    return (1) 
  end 
  
  -- Only the SA or the dbo of @dbname can execute the update part 
  -- of this procedure sys.so check. 
  if (not (is_srvrolemember('sysadmin') = 1)) and suser_sid() <> @dbsid 
    -- ALSO ALLOW db_owner ONLY IF DB REQUESTED IS CURRENT DB 
    and (@dbid <> db_id() or is_member('db_owner') <> 1) 
  begin 
    raiserror(15418,-1,-1) 
    return (1) 
  end 
  
  -- If we're in a transaction, disallow this since it might make recovery impossible. 
  set implicit_transactions off 
  if @@trancount > 0 
  begin 
    raiserror(15002,-1,-1,'sys.sp_dbcmptlevel') 
    return (1) 
  end 
  
  set @exec_stmt = 'ALTER DATABASE ' + quotename(@dbname, '[') + ' SET COMPATIBILITY_LEVEL = ' + cast(@input_cmptlevel as nvarchar(128)) 
  
  -- Note: database @dbname may not exist anymore 
  exec(@exec_stmt) 
  
  select @new_cmptlevel = @input_cmptlevel 
  
  return (0) -- sp_dbcmptlevel 
 GO 

sp_dbcmptlevel [ [ @dbname = ] name ] [ , [ @new_cmptlevel = ] version ] 

[ @dbname = ] name