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

DB2
Copy codeThe 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 ):
Copy codeThe 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
Copy codeThe Code is as follows: create table T1
(
Id int not null AUTO_INCREMENT,
...
);

PostgreSQL
Copy codeThe Code is as follows: create table T1
(
Id serial not null,
...
);

SQL Server
Copy codeThe Code is as follows: create table T1
(
Id int not null identity,
...
);

Sybase
Copy codeThe Code is as follows: create table T1
(
Id int not null identity,
...
);