Prior to DBMS_SCHEDULE
, the way to specify the repeating interval with the DBMS_JOB
was pretty complex, and not very easy to read. The time expressions were PL/SQL expressions that resulted in a rigid schedule pattern. The syntax used by the Scheduler time is far more flexible and powerful, and, among many other features, the richness of the time expressions is one of the Scheduler's strengths.
The repeat interval goes from as little as seconds, to years. The frequency can be defined seconds, minutes, hours, days, weeks, months, and years.
The syntax used to write time intervals can be specified either using a regular schedule or a combined schedule.
repeat_interval = regular_schedule | combined_schedule