Illustration strms034.gif shows the following process for row migration during apply:
A user makes the following update to a table:
UPDATE hr.employees SET department_id=50 WHERE employee_id=145;
The source database records the change in the redo log.
A capture process captures the change and enqueues it as an LCR into a queue at the source database.
The propagation propagates the LCR to a queue at the destination database.
An apply process dequeues the LCR at the destination database and transforms the
UPDATE into an
INSERT because the change satisfies a subset rule.
The apply process applies the change as an
INSERT into an
hr.employees subset table. This subset table contains rows only for employees with a
department_id equal to