CHECK constraint on date of birth?

Question

I am creating my employee table in Oracle and for emp_date I would like to make it so the date of birth is not way back in the past and can not be set in the future?

Answer 1

You can use interval directly:

ALTER TABLE "students"
  ADD CONSTRAINT "students_must_be_over_18" CHECK (
    CURRENT_TIMESTAMP - "date_of_birth" > INTERVAL '18 years'
  );