Trigger with REFERENCING and WHEN clauses : Introduction « Trigger « Oracle PL/SQL Tutorial

1. Oracle PL/SQL Tutorial
2. Trigger
3. Introduction

SQL>
SQL> create table company(
  2     product_id        number(4)    not null,
  3     company_id          NUMBER(8)    not null,
  4     company_short_name  varchar2(30) not null,
  5     company_long_name   varchar2(60)
  6  );

Table created.

SQL> create table product_audit(
  2     product_id number(4) not null,
  3     num_rows number(8) not null
  4  );

Table created.

SQL>
SQL>
SQL>
SQL>
SQL> CREATE OR REPLACE TRIGGER myTrigger
  2  AFTER INSERT ON company
  3  REFERENCING NEW AS new_org
  4  FOR EACH ROW
  5  WHEN (new_org.product_id <>1)
  6  BEGIN
  7    UPDATE product_audit
  8    SET num_rows =num_rows+1
  9    WHERE product_id =:new_org.product_id;
 10    IF (SQL%NOTFOUND) THEN
 11      INSERT INTO product_audit VALUES (:new_org.product_id,1);
 12    END IF;
 13  END;
 14  /

Trigger created.

SQL>
SQL>
SQL> insert into company values(1,1001,'A Inc.','Long Name A Inc.');

1 row created.

SQL> insert into company values(1,1002,'B Inc.','Long Name B Inc.');

1 row created.

SQL> insert into company values(1,1003,'C Inc.','Long Name C Inc.');

1 row created.

SQL> insert into company values(2,1004,'D Inc.','Long Name D Inc.');

1 row created.

SQL> insert into company values(2,1005,'E Inc.','Long Name E Inc.');

1 row created.

SQL> insert into company values(2,1006,'F Inc.','Long Name F Inc.');

1 row created.

SQL>
SQL>
SQL>
SQL>
SQL> drop table product_audit;

Table dropped.

SQL>
SQL> drop table company;

Table dropped.

SQL>