摘要:
添加约束:alter table table1 add constraintpk_name primary key (name) --添加主健约束,名称作为主健; alter table table1 add constraintpk_nameunique (name) --添加唯一约束,名称不能重复; alter table table1add constraint df_address default('地点不详') for saddress --添加默认约束,地点不详; alter table table1add constraint ck_age check (ages 阅读全文