例如alter table Person
add nl int not null default'0'
go
alter table Person alter column nl drop default
go
会报错服务器: 消息 156,级别 15,状态 1,行 1
在关键字 'default' 附近有语法错误。如何删去设置了约束的字段啊
add nl int not null default'0'
go
alter table Person alter column nl drop default
go
会报错服务器: 消息 156,级别 15,状态 1,行 1
在关键字 'default' 附近有语法错误。如何删去设置了约束的字段啊
drop constraint 约束名
set @tablename = 'XXX' --表名
set @columnname= 'XXXX' --字段名称declare @defname varchar(100) --约束名称
declare @cmd varchar(100) --构造的SQL语句
select @defname = name from sysobjects so join sysconstraints sc on so.id = sc.constid where object_name(so.parent_obj) = @tablename
and so.xtype = 'd' and sc.colid =(select colid from syscolumns where id = object_id(@tablename) and name = @columnname)
select @cmd= 'alter table '+ @tablename+ ' drop constraint '+ @defname if @cmd is null print ' no default constraint to drop'
exec (@cmd)
drop table tb
go
create table tb(Id int ,col varchar(10) default 'AA')
go
select b.name
from syscolumns a,sysobjects b
where a.id=object_id('tb') and b.id=a.cdefault and b.name like 'DF%'
/*
DF__tb__col__051E8AB9
*/