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

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m (Replacing page with ' '''Warning See "About Object-Relational Mapping" in the [http://www.eclipse.org/eclipselink/documentation/ EclipseLink Concepts Guide]'''')
 
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{{EclipseLink_UserGuide
 
|info=y
 
}}
 
=orm.xml=
 
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">
 
    <jta-data-source>jdbc/EmployeeServiceDS</jta-data-source>
 
    <mapping-file>META-INF/employee_service_queries.xml</mapping-file>
 
</persistence-unit>
 
</source>
 
{{EclipseLink_Note
 
|note=In this example, the '''orm.xml''' file is not listed -- the persistence provider finds it by default.
 
}}
 
  
  
 
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'''[[Image:Elug_draft_icon.png|Warning]] See "About Object-Relational Mapping" in the [http://www.eclipse.org/eclipselink/documentation/ EclipseLink Concepts Guide]'''
==Advantages and Disadvantages of Using XML==
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Some advantages of using XML instead of [[EclipseLink/UserGuide/JPA/Basic JPA Development/Configuration/JPA/Annotations|Annotations]] include:
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* No coupling between the metadata and the source code
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* Compliance with the existing, pre-EJB 3.0 development process
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* Support in IDEs and source control systems
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The main disadvantages of mapping with XML include:
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*Its inherent complexitiy (when compared to annotations)
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*The need for replication of the code context
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{{EclipseLink_JPA
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|previous=[[EclipseLink/UserGuide/JPA/Basic JPA Development/Configuration/JPA/Annotations|Annotations]]
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|next=[[EclipseLink/UserGuide/JPA/Basic JPA Development/Configuration/JPA/Defaults|Defaults]]
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|up=[[EclipseLink/UserGuide/JPA/Basic JPA Development/Configuration|Configuration]]
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|version=2.1.0}}
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Latest revision as of 10:49, 25 January 2013


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