PersistentManager and Transaction
PersistentManager is used to manage database connection, state of the persistent objects and transaction when the application is running. A database transaction is a unit of the application. It is used to keep integrity of your data in database. Our Persistent Library provides a transaction API for you to create, commit and rollback the transaction for your application.
Start Transaction
When you need to start a transaction, you need to get the session from the PersistentManager and call the beginTransaction function (PersistentManager.instance().getSession().beginTransaction();). Here is a sample:
Commit Transaction
After you have inserted/updated/deleted data, you can call the commit function of the transaction object to commit your changes to Database.
Rollback Transaction
In case there are any exception, you can call the rollback function to cancel all the operation.
Sample Code
The following is an example of using the transaction API.
PersistentTransaction t = SchoolSystemPersistentManager.instance().getSession().beginTransaction();
try {Course lCourse = CourseFactory.createCourse();
lCourse.setTitle(getTitleTextField().getText());
lCourse.setDescription(getDescriptionTextField().getText());
lCourse.setTeacher(_teacher);
_teacher.save();
t.commit();
return lCourse;
} catch (Exception e) {
e.printStackTrace();
t.rollback();
}
return null;
}
Related Resources
The following resources may help you to learn more about the topic discussed in this page.
| 3. Generating ORM code from class diagram | Table of Contents | 5. Using ORM Qualifier |
