5-1. Automatically Generating Column Values
You want to automatically generate certain column values for newly inserted rows. For example, one of your tables includes a date field that you want to have populated with the current date when a record is inserted.
Create a trigger that executes
BEFORE INSERT on the table. The trigger will capture the system date and populate this date field with it prior to inserting the row into the database. The following code demonstrates how to create a trigger that provides this type of functionality for your application. In the example, the
EMPLOYEES table is going to have its
HIRE_DATE populated with the current date when a record is inserted into the
CREATE or REPLACE TRIGGER ...