sql语句添加删除外键

--删除外键
alter table HelpTextInfo drop constraint HelpTextInfo_Helptype_FK1

--增加外键
alter   table HelpTextInfo add constraint HelpTextInfo_Helptype_FK1 foreign key (helptypeid) references Helptype(helptypeid)

--不检查约束
alter table HelpTextInfo nocheck constraint HelpTextInfo_Helptype_FK1

--检查约束
alter table HelpTextInfo check constraint HelpTextInfo_Helptype_FK1