--SQLSERVER的自定义类型比较好用吧，但是，一旦引用该数据类型后，想修改数据类型，就是一大头疼的事了，本存储过程就是专门对付它的。 --sp_rebuildallview 见本BLOG中的其它页面 create procedure sp_rechangfieldtype(@typename varchar(50), @newtype v
--SQLSERVER的自定义类型比较好用吧，但是，一旦引用该数据类型后，想修改数据类型，就是一大头疼的事了，本存储过程就是专门对付它的。 --sp_rebuildallview 见本BLOG中的其它页面 create procedure sp_rechangfieldtype(@typename varchar(50), @newtype varchar(50)) as begin
declare @typeid int declare @tablename varchar(50) declare @column varchar(50)
declare @sqlstr varchar(200) declare @defaultid int
select @typeid = xusertype from systypes where name = @typename and xusertype > 256 AND (is_member('db_owner') = 1 OR is_member('db_ddladmin') = 1 OR is_member(user_name(uid))=1)
declare mycursor cursor for select o.name, c.name, c.cdefault from syscolumns c, systypes t, sysusers u, sysobjects o where c.xusertype = @typeid and t.xusertype = @typeid and o.uid = u.uid and c.id = o.id and o.type = 'u'
open mycursor fetch next from mycursor into @tablename, @column, @defaultid while @@fetch_status = 0 begin if @defaultid 0 begin set @sqlstr = 'alter table ' + @tablename + ' drop ' + object_name(@defaultid) exec(@sqlstr)
set @sqlstr = 'alter table ' + @tablename + ' alter column ' + @column + ' ' + @newtype exec(@sqlstr) -- set @sqlstr = 'alter table ' + @tablename + ' add contraint ' + @tablename + 'df'+@column + ' default 0'
end else begin set @sqlstr = 'alter table ' + @tablename + ' alter column ' + @column + ' ' + @newtype
print @sqlstr exec(@sqlstr) end --if @@error 0 -- continue fetch next from mycursor into @tablename, @column, @defaultid end --如果没有约束，则可以直接删除。如果有约束。先处理约束。
close mycursor deallocate mycursor
end GO create procedure SP_CHANGEFIELD(@OLDTYPENAME VARCHAR(50), @NEWDTYPE VARCHAR(50)) as begin
exec('sp_addtype U_LOCALTYPE, ''' + @newdtype + '''')
exec SP_rechangfieldtype @OLDTYPENAME, 'U_LOCALTYPE'
EXEC sp_rebuildallview
EXEC('sp_droptype ' + @OLDTYPENAME)
EXEC('sp_addtype ' + @OLDTYPENAME + ', ''' + @newdtype + '''')
exec SP_rechangfieldtype 'U_LOCALTYPE', @OLDTYPENAME
EXEC sp_rebuildallview
EXEC sp_droptype 'U_LOCALTYPE'
end GO
--以下是示例。将U_HELLO的长度改为 30 SP_ADDTYPE U_HELLO, 'VARCHAR(10)'
GO CREATE TABLE TESTTYPE(NAME U_HELLO) GO
SP_CHANGEFIELD 'U_HELLO', 'VARCHAR(30)'