浅析常用数据库的自增字段创建方法汇总

飞奔的炮台

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, 
   ...
);