sql常用语句

sql server 查看指定表约束

select * from sysobjects where parent_obj in(
select id from sysobjects where name='student')

sp_mshelpcolumns student

删除约束

alter table tablename drop constraint PK_tablename 去掉

alter table name add constraint pk_tablename primary key clunstered (b）--增加 

临时停用约束

禁用：
ALTER TABLE table_name NOCHECK CONSTRAINT constraint_name

ALTER TABLE table_name NOCHECK CONSTRAINT ALL    --禁用所有约束

启用：
ALTER TABLE table_name CHECK CONSTRAINT constraint_name

ALTER TABLE table_name CHECK CONSTRAINT ALL    --启用所有约束