오라클의 virtual column 구현하기

---------------- 오라클 예제 ---------------

CREATE TABLE EMP (
SABUN NUMBER,
SAL NUMBER,
BONUS NUMBER,
TOTAL_SAL NUMBER  GENERATED ALWAYS AS (sal*12 + bonus)
);

insert into emp(sabun, sal,bonus) values(1,3000,200);

select * from emp;

     SABUN        SAL      BONUS  TOTAL_SAL
---------- ---------- ---------- ----------
         1       3000        200      36200

-----------------------------------------------------------------------------------

PostgreSQL 과 EPAS 는 아래와 같이 위 기능을 구현할수 있습니다.

CREATE TABLE EMP (
SABUN NUMBER,
SAL NUMBER,
BONUS NUMBER
);

CREATE FUNCTION TOTAL_SAL(EMP) RETURNS number AS $$
    SELECT $1.sal*12 + $1.bonus
$$ LANGUAGE SQL;

insert into emp(sabun, sal,bonus) values(1,3000,200);

select * from emp;
+-------+------+-------+
| sabun | sal  | bonus |
+-------+------+-------+
|     1 | 3000 |   200 |
+-------+------+-------+
(1 row)

select a.*, a.total_sal from emp a;
+-------+------+-------+-----------+
| sabun | sal  | bonus | total_sal |
+-------+------+-------+-----------+
|     1 | 3000 |   200 |     36200 |
+-------+------+-------+-----------+
(1 row)