--这样改就行了.alter table INV_ItemMaster drop constraint DF_INV_ItemMaster_nItemTypeId
goALTER TABLE INV_ItemMaster ALTER column nItemTypeId char(20) not null
goALTER TABLE INV_ItemMaster ALTER column nItemTypeId char(20) not null
set @s=''
select @s=@s+'
alter table ['+b.name+'] drop constraint ['+d.name+']'
from syscolumns a
join sysobjects b on a.id=b.id
join syscomments c on a.cdefault=c.id
join sysobjects d on c.id=d.id
where b.name='INV_ItemMaster' and a.name='nItemTypeId'
exec(@s)ALTER TABLE INV_ItemMaster ALTER column nItemTypeId char(20) not null