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Difference between revisions of "EclipseLink/UserGuide/JPA/Basic JPA Development/Configuration/JPA/orm.xml"

m (Replacing page with ' '''Warning See "About Object-Relational Mapping" in the [ EclipseLink Concepts Guide]'''')
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Use the '''orm.xml''' file to apply the metadata to the persistence unit. This metadata is a union of all the mapping files and the annotations (if there is no '''xml-mapping-metadata-complete'''  element). If you use one mapping '''orm.xml''' file for your metadata and place this file in a META-INF directory on the classpath, then you do not need to explicitly list it. The EclipseLink persistence provider will automatically search for this file ('''orm.xml''') and use it.
If you use a different name for your mapping files or place them in a different location, you must list them in the '''mapping-file''' element of the [[EclipseLink/UserGuide/JPA/Basic_JPA_Development/Configuration/JPA/persistence.xml|persistence.xml file]], as shown here:
<source lang="xml">
<persistence-unit name="EmployeeService">
|note=In this example, the '''orm.xml''' file is not listed -- the persistence provider finds it by default.
'''[[Image:Elug_draft_icon.png|Warning]] See "About Object-Relational Mapping" in the [ EclipseLink Concepts Guide]'''
==Advantages and Disadvantages of Using XML==
Some advantages of using XML instead of [[EclipseLink/UserGuide/JPA/Basic JPA Development/Configuration/JPA/Annotations|Annotations]] include:
* No coupling between the metadata and the source code
* Compliance with the existing, pre-EJB 3.0 development process
* Support in IDEs and source control systems
The main disadvantages of mapping with XML include:
* Its inherent complexitiy (when compared to annotations)
* The need for replication of the code context
|previous=[[EclipseLink/UserGuide/JPA/Basic JPA Development/Configuration/JPA/Annotations|Annotations]]
|next=[[EclipseLink/UserGuide/JPA/Basic JPA Development/Configuration/JPA/Defaults|Defaults]]
|up=[[EclipseLink/UserGuide/JPA/Basic JPA Development/Configuration|Configuration]]
|version=2.2.0 DRAFT}}

Latest revision as of 11:49, 25 January 2013

Warning See "About Object-Relational Mapping" in the EclipseLink Concepts Guide

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