sql 创建约束
--drop table index_tb create table index_tb(id int constraint ck_id default 0,name varchar(20),xb varchar(2)) --查看表 exec sp_helpindex orders--索引 exec sp_helpconstraint index_tb --约束 exec sp_fkeys 'dbo.Person'--外键 --键不唯一,非聚集索引 create index id_index on index_tb(id) --删除索引 drop index index_tb.id_index --键聚集索引 create clustered index id_index on index_tb(id) --删除索引 drop index index_tb.id_index --创建check约束 alter table index_tb add constraint ck_index CHECK (name like '[0-9][0-9][0-9][0-9][0-9]') alter table index_tb add constraint ck2_index check(xb in ('MM','GG')) --删除check约束 alter table index_tb drop constraint ck2_index --禁止表约束 alter table index_tb nocheck constraint ck_index --恢复表约束 alter table index_tb check constraint ck_index --禁止和恢复所有check-all关键字 select 'alter table '+name+' nocheck or check constraint all' from sysobjects where type='U' --添加新默认值和约束 ALTER TABLE index_tb ADD CONSTRAINT de_name DEFAULT ('11111') FOR name --删除表约束 alter table index_tb drop constraint de_name -- 字段 UNIQUE NOT NULL = PRIMARY KEY 差不多 --创建unique alter table index_tb add constraint uniqueindex unique(id) --删除unique alter table index_tb drop constraint uniqueindex insert into index_tb(name,xb) select '12345','mm' select * from index_tb delete index_tb