Analysis on the methods for creating auto-increment fields in common databases

This article provides a comprehensive overview of the methods for creating auto-incrementing fields in common databases. For more information, see the following DB2 copy code: CREATETABLET1 (idINTEGERNOTNULLGENERATEDALWAYSASIDENTITY (unique

This article provides a comprehensive summary of the methods for creating auto-incrementing fields in common databases. For more information, see the following DB2 code: 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

This article provides a comprehensive summary of the methods for creating auto-incrementing fields in common databases. For more information, see

DB2

The Code is as follows:

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 (you need to create a SEQUENCE and a TRIGGER ):

The Code is as follows:

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

The Code is as follows:

Create table T1
(
Id int not null AUTO_INCREMENT,
...
);

PostgreSQL

The Code is as follows:

Create table T1
(
Id serial not null,
...
);

SQL Server

The Code is as follows:

Create table T1
(
Id int not null identity,
...
);

Sybase

The Code is as follows:

Create table T1
(
Id int not null identity,
...
);