通过更新系统表来直接完成类型更新。
declare @Type_ntext int, @Type_varchar int
select xtype from systypes where name='ntext'
select xtype from systypes where name='varchar'
update syscolumns
set xtype = @Type_varchar
where xtype = @Type_ntext
declare @Type_ntext int, @Type_varchar int
select xtype from systypes where name='ntext'
select xtype from systypes where name='varchar'
update syscolumns
set xtype = @Type_varchar
where xtype = @Type_ntext
--更新前
exec sp_configure 'allow update',1
reconfigure with override--更新操作--更新后
exec sp_configure 'allow update',0
reconfigure with override