浅析常用数据库的自增字段创建方法汇总

db2

create   table  t1
(
   id  integer   not   null  generated always  as   identity  (start  with   1  increment  by   1  minvalue  1  no maxvalue no cycle no cache  order ),
   ...
);

oracle（需要创建一个sequence和一个trigger）：

create table t1
(
   id number(10,0) not null,
   ...
);
create sequence t1_id_seq increment by 1 start with 1 nomaxvalue nocycle cache 100 order;
create or replace trigger insert_t1_id
before insert on t1
referencing new as new old as old
for each row
begin
    select t1_id_seq.nextval into :new.id from dual;
end;

mysql

create table t1
(
   id int not null auto_increment,
   ...
);

postgresql

create table t1
(
   id serial not null,
   ...
);

sql server

create table t1
(
   id int not null identity,
   ...
);

sybase

create table t1
(
   id int not null identity,
   ...
);