SQL??????????

???????????????SQL????????????????????SQL?????????????????????????SQL????????????????????
???????SQL??????????
????alter table ???? drop constraint ???????
?????????????????ε???????
????alter table ???? add constraint ??????? DEFAULT ???? for ???????
????????????????????ε?????????????
????go
????????
????alter table T_ping drop constraint DF_T_ping_p_c
????alter table T_ping add constraint DF_T_ping_p_c DEFAULT ((2)) for p_c
????go
??????????????????
????select b.text as ????????? ???????
????from syscolumns a left join syscomments b on a.cdefault=b.id
????where a.id=object_id('????') and a.name='???????'
?????????syscolumns ??syscomments?????
????????
????select b.text as moren
????from syscolumns a left join syscomments b on a.cdefault=b.id
????where a.id=object_id('T_ping') and a.name='p_c'
?????????????????????????????