从SQLSERVER6.5开始,MS提供了一个非常有用的系统存储过程sp_MSforeachtable和sp_MSforeachDB;作为DBA会经常需要检查所有的数据库或用户表,比如:检查所有数据库的容量;看看指定数据库所有用户表的容量,所有表的记录数...,我们一般处理这样的问题都是用游标分别处理处理,比如:在数据库检索效率非常慢时,我们想检查数据库所有的用户表,我们就必须这样写游标:DECLARE @TableName varchar(255)DECLARE @ExeSQL varchar(4000)
DECLARE Table_Cursor CURSOR FOR SELECT [name] FROM sysobjects WHERE xtype='U'
OPEN Table_CursorFETCH NEXT FROM Table_Cursor INTO @TableName
WHILE(@@FETCH_STATUS=0)BEGIN PRINT @TableName SELECT @ExeSQL='DBCC CHECKTABLE(''' @TableName ''')' EXEC(@EXESQL)FETCH NEXT FROM Table_Cursor INTO @TableNameEND
CLOSE Table_CursorDEALLOCATE Table_CursorGO
如果我们用sp_MSforeachtable就可以非常方便的达到相同的目的:EXEC sp_MSforeachtable @command1="print '?' DBCC CHECKTABLE('?')"大家可以看出这样就更加简洁(虽然在后台也是通过游标来处理的),下面我们就仔细分析一下sp_MSforeachtable这个存储过程:
我们看看sp_MSforeachtable详细的CODE:USE MASTER GOSP_HELPTEXT sp_MSforeachtable
--下面时sp_MSforeachtable的原始代码
CREATE proc sp_MSforeachtable @command1 nvarchar(2000), @replacechar nchar(1) = N'?', @command2 nvarchar(2000) = null, @command3 nvarchar(2000) = null, @whereand nvarchar(2000) = null, @precommand nvarchar(2000) = null, @postcommand nvarchar(2000) = nullas /* This proc returns one or more rows for each table (optionally, matching @where), with each table defaulting to its
own result set */ /* @precommand and @postcommand may be used to force a single result set via a temp table. */
/* Preprocessor won't replace within quotes so have to use str(). */ declare @mscat nvarchar(12) select @mscat = ltrim(str(convert(int, 0x0002)))
if (@precommand is not null) exec(@precommand)
/* Create the select */ exec(N'declare hCForEach cursor global for select ''['' REPLACE(user_name(uid), N'']'', N'']]'') '']'' ''.'' ''[''
REPLACE(object_name(id), N'']'', N'']]'') '']'' from dbo.sysobjects o ' N' where OBJECTPROPERTY(o.id, N''IsUserTable'') = 1 ' N' and o.category & ' @mscat N' = 0 ' @whereand) declare @retval int select @retval = @@error if (@retval = 0) exec @retval = sp_MSforeach_worker @command1, @replacechar, @command2, @command3
if (@retval = 0 and @postcommand is not null) exec(@postcommand)
return @retval
这个系统存储过程有7个参数: @command1 nvarchar(2000), --第一条运行的T-SQL指令 @replacechar nchar(1) = N'?', --指定的占位符号 @command2 nvarchar(2000) = null,--第二条运行的T-SQL指令 @command3 nvarchar(2000) = null, --第三条运行的T-SQL指令 @whereand nvarchar(2000) = null, --可选条件来选择表 @precommand nvarchar(2000) = null, --在表前执行的指令 @postcommand nvarchar(2000) = null --在表后执行的指令
所以上面的语句也可以这样写:EXEC sp_MSforeachtable @command1="print '?'", @command2= "DBCC CHECKTABLE('?')"
了解参数以后,就让我们做几个实列吧:1.获得每个表的记录数和容量:EXEC sp_MSforeachtable @command1="print '?'", @command2="sp_spaceused '?'", @command3= "SELECT count(*) FROM ? "
2.更新PUBS数据库中已t开头的所有表的统计:EXEC sp_MSforeachtable @whereand="and name like 't%'", @replacechar='*', @precommand="print 'Updating Statistics.....' print ''", @command1="print '*' update statistics * ", @postcommand= "print''print 'Complete Update Statistics!'"
sp_MSforeachDB除了@whereand外,和sp_MSforeachtable的参数是一样的,我们可以通过这个存储过程检测所有的数据库,比如:1.获得所有的数据库的存储空间: EXEC sp_MSforeachdb @command1="print '?'", @command2="sp_spaceused "2.检查所有的数据库 EXEC sp_MSforeachdb @command1="print '?'", @command2="DBCC CHECKDB (?) "
有了上面的分析,我们可以建立自己的sp_MSforeachObject:USE MASTERGOCREATE proc sp_MSforeachObject @objectType int=1, @command1 nvarchar(2000), @replacechar nchar(1) = N'?', @command2 nvarchar(2000) = null, @command3 nvarchar(2000) = null, @whereand nvarchar(2000) = null, @precommand nvarchar(2000) = null, @postcommand nvarchar(2000) = null as /* This proc returns one or more rows for each table (optionally, matching @where), with each table defaulting to its
own result set */ /* @precommand and @postcommand may be used to force a single result set via a temp table. */
/* Preprocessor won't replace within quotes so have to use str(). */ declare @mscat nvarchar(12) select @mscat = ltrim(str(convert(int, 0x0002)))
if (@precommand is not null) exec(@precommand)
/* Defined @isobject for save object type */ Declare @isobject varchar(256)
select @isobject= case @objectType when 1 then 'IsUserTable' when 2 then 'IsView' when 3 then 'IsTrigger' when 4 then 'IsProcedure' when 5 then 'IsDefault' when 6 then 'IsForeignKey' when 7 then 'IsScalarFunction' when 8 then 'IsInlineFunction' when 9 then 'IsPrimaryKey' when 10 then 'IsExtendedProc' when 11 then 'IsReplProc' when 12 then 'IsRule' end
/* Create the select */ /* Use @isobject variable isstead of IsUserTable string */EXEC(N'declare hCForEach cursor global for select ''['' REPLACE(user_name(uid), N'']'', N'']]'') '']'' ''.'' ''[''
REPLACE(object_name(id), N'']'', N'']]'') '']'' from dbo.sysobjects o ' N' where OBJECTPROPERTY(o.id, N''' @isobject ''') = 1 ' N' and o.category & ' @mscat N' = 0 ' @whereand)
declare @retval int select @retval = @@error if (@retval = 0) exec @retval = sp_MSforeach_worker @command1, @replacechar, @command2, @command3
if (@retval = 0 and @postcommand is not null) exec(@postcommand)
return @retval
GO这样我们来测试一下:1.获得所有的存储过程的脚本: EXEc sp_MSforeachObject @command1="sp_helptext '?' ",@objectType=42.获得所有的视图的脚本: EXEc sp_MSforeachObject @command1="sp_helptext '?' ",@objectType=23.比如在开发过程中,没一个用户都是自己的OBJECT OWNER,所以在真实的数据库时都要改为DBO: EXEc sp_MSforeachObject @command1="sp_changeobjectowner '?', 'dbo'",@objectType=1 EXEc sp_MSforeachObject @command1="sp_changeobjectowner '?', 'dbo'",@objectType=2 EXEc sp_MSforeachObject @command1="sp_changeobjectowner '?', 'dbo'",@objectType=3 EXEc sp_MSforeachObject @command1="sp_changeobjectowner '?', 'dbo'",@objectType=4 这样就非常方便的将每一个数据库对象改为DBO.
当然还要很多非常好的功能,大家可以自己深入研究吧:-)