ORACLE-检查日期触发器

Question

Why this code doesn't work in ORACLE ?

CREATE TRIGGER chk_dates
BEFORE INSERT ON `job_history`
FOR EACH ROW
BEGIN
  IF (NEW.end_date < NEW.start_date) THEN
    SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = 'end_date cannot be earlier than start_date';
  END IF;
END;

I have a log: ORA-00911:"invalid character"

Answer 1

You are mixing MySQL syntax with Oracle. There is no SIGNAL SQLSTATE in Oracle.

In Oracle, use raise_application_error to raise error.

BEGIN
  IF (:NEW.end_date < :NEW.start_date) THEN
    raise_application_error(-20001, 'end_date cannot be earlier than start_date');
  END IF;
END;

In this case, you don't even need a trigger as this can be easily achieved using a check constraint like this:

alter table your_table
add constraint contraint_name check (end_date >= start_date);