Question

I have a simple web-app with Database with two tables.

The administrators can modified the first table manually directly from SQL script (for example with PHPMyAdmin) and my web-app should be write into second tables some data after this edit.

Can I do it?

Answer 1

You can use the @PrePersist Annotation:
http://docs.oracle.com/javaee/5/api/javax/persistence/PrePersist.html

 public final class SampleBusinessProcess {

    @PrePersist
    private void preperist(final MyObject obj) {
      entityManager.store(new Object2());
    }

 }

This will store a second entity into another table, if the first one is modified.

edit:
A trigger cannot start a JPA-code. That is not part of JPA.

A trigger within an Oracle Database may start a piece of Java Code as a java-trigger.

I assume you are using a mysql-database, so you’ll have to create a trigger at databaselevel an a timerservice which will poll the second table for changes.