create table tb_student( id NUMBER(10) not null, createtime DATE not null, constraint PK_tb_student PRimary key (id));comment on table "tb_student" is'学生表';comment on column "tb_student"."id" is'主键id';comment on column "tb_student"."createtime" is'创建时间';--创建序列create sequence seq_tb_studentminvalue 1nomaxvaluestart with 1increment by 1nocycle --一直累加,不循环--nocache; --不缓存cache 10; --缓存10条--创建触发器,如果insert语句不指定ID自动插入增长值CREATE OR REPLACE TRIGGER tr_tb_student BEFORE INSERT ON tb_student FOR EACH ROW WHEN (new.id is null)beginselect seq_tb_student.nextval into:new.id from dual;end;//其他方法法一:
123456 | create table tb_student ( id integer generated by default as identity not null constraint PK_tb_student primary key , createtime DATE not NULL ); |
123456789101112131415 | --创建序列 create sequence seq_tb_student minvalue 1 nomaxvalue start with 1 increment by 1 nocycle --一直累加,不循环 nocache; create table tb_student ( id integer default seq_tb_student.nextval not null constraint PK_tb_student primary key , createtime DATE not NULL ); |
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