[Oracle]指定sequence為欄位identify

Altering an IDENTITY Column

參考:Oracle 如何做到 SQL Server 的 Identity 欄位型態 - Yowko's Notes

         https://www.oracletutorial.com/oracle-basics/oracle-identity-column/

Oracle 12c introduced a new way that allows you to define an identity column for a table, which is similar to the AUTO_INCREMENT column in MySQL or IDENTITY column in SQL Server.

**Oracle原本無identity用法

--1. 先移除原本存在的IDENTITY

ALTER TABLE test_tb (MODIFY pk_id DROP IDENTITY);

--2. 指定sequence給pk_id 

alter table test_tb modify pk_id default on null test_tb_seq .nextval;

-- CREATE SEQUENCE

CREATE SEQUENCE test_tb_seq 

    START WITH 1

    INCREMENT BY 1

    MAXVALUE 9999999999999999999999999999

    CACHE 20

    CYCLE