--自动编号：Oracle 建表 create table t1(autoid number(10) primary key,name char(4)); 创建序列 create sequence seq_t1_autoid; 添加数据 insert into t1(autoid,name) values(seq_t1_autoid.nextval,'a'); insert into t1(autoid,name) values(seq_t1_autoid.nextVal,'b'); commit; --思考：能不能实现一个与DBMS无关的自动编号方法? insert into t1(autoid,name) select max(autoid)+1,'c' from t1; insert into t1(autoid,name) select max(autoid)+1,'d' from t1; commit; --改正： insert into t1(autoid,name) select nvl(max(autoid),0)+1,'c' from t1; insert into t1(autoid,name) select nvl(max(autoid),0)+1,'d' from t1; commit; 面试：如何在Oracle中实现与Mysql一样的自动编号： 解决：使用触发器
create table t1(autoid number(10) primary key); create sequence seq_t1_autoid; create or replace trigger tr_t1_autoid before insert on Friend for each row begin select seq_t1_autoid.nextval into :new.autoid from dual; end; --测试： insert into t1(name) values('a'); insert into t1(name) values('b'); commit; select * from t1; autoid name 1 a 2 b +--------+------+
