# The persistence.xml file

The JPA specification requires the use of a `persistence.xml` file for deployment. This file defines the database and entity manager options, and may contain more than one persistence unit.

To enable you to easily edit this information, Dali provides the persistence.xml Editor. Alternatively, you can use the Eclipse XML Editor to create and maintain this information. See "Managing the persistence.xml file" for more information.

Tip: To work with multiple persistence units, comment out all but one persistence unit in `persistence.xml`.

Related tasks

- Managing the persistence.xml file

- Creating a new JPA project

Related reference

- Section 8.2.1 "persistence.xml file" in the JPA Specification