Persistence Configuration Editor

The Persistence Configuration Editor lets you configure the persistence units you use in your project and the extending projects.

Usually you only need a single persistence unit that manages all of your project’s entity data classes. In this case you can simply create a new persistence unit, associate it with a data source (i.e. data base) and you’re done. All of the project’s entity classes will then automatically be managed by this unit.

However, if you wish to do so, you can divide your entity data classes into subsets and manage each subset through an individual persistence unit. In this case you need to specify multiple persistence units and then define an explicit list of managed entity classes for each unit.

Warning

Although it is theoretically possible to have the same entity class managed by two or more persistence units, you should be aware of the consequences. Once you have generated/attached an object of a specific class through a specific persistence unit, you must ensure that it is managed uniquely by that unit afterwards.

Example: Assume that you have two different objects of the same entity class, e.g. Person, generated through different persistence units, e.g. employee through employee_unit and customer through customer_unit. In this case you must absolutely avoid to mix persistence units and objects. For the above example, handing over employee to customer_unit (or customer to employee_unit) will consequently result in errors.

Persistence Configuration Editor (single persistence unit)

Persistence Configuration Editor (multiple persistence units)

New

Add a new persistence unit configuration

Remove

Remove the selected persistence unit(s)

Generate Schema

Generates the database schema out of the entity classes who belong to the selected persistence unit. See Generate database schema from persistence unit for details.

Accessibility

Axon.ivy Project Tree > double click on the Persistence label.

Features

Data source

Here you have to choose a database configuration which will be the data source of this persistence unit. Means all the data are loaded and stored within this database. Go to the Database Configuration Editor to configure available datasources.

There is also an IvySystemDatabase datasource which points to the current System Database. Normally you would prefer your own database to split valuable customer data from the system data.

Description

You can give your persistence unit any description here.

Managed Classes

Specify the list of classes to be managed in this persistence unit. If ‘Exclude unlisted classes’ is checked, only the entity classes which are defined in the list are included in the persistence unit. Otherwise all entity classes of the project are included automatically plus the entity classes defined in the list.

Properties

Specify some properties for the persistence unit. You do not have to specify something here except you now what you are doing.