oracle认证应用技术学习资料汇总2
约束状态enable validate:是默认,新旧数据同时满足约束规则
enable novalidate:旧数据可以不满足,检新插入的数据要满足约束
disable validate:不允许在表上执行任何DML操作,主要用在分区表,对于主键和唯一约事,会删除相应的唯一索引,但约束状态任可用
disable novalidate数据可不满足约束规则,对于主键和唯一约事,会删除相应的唯一索引,
约束常用语句
create table t(i number,v mubmer not null)
create table t(i number,v mubmer unique)
create table t(i number constraint pk_i primary key,v number)
create table t2(c number,d number,constraint fk_d foreign key(c),references t1(v));
alter table t add constraint pk_i primary key (i)
alter table t modify i not null;
alter table t add constraint t_i unique(i)[(create index ind_name on t(i))];
alter table t add constraint t_i check(i in (1,2,3,4,5));
alter table t disable novalidate constraint i
alter table t enable novalidate constraint check_i
alter table t drop constraint i;
alter table t drop primary key i;
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