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Difference between revisions of "Talk:EclipseLink/UserGuide/JPA/Basic JPA Development/Mapping/Basic Mappings/Default Conversions and Converters/StructConverter"
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::* [[Introduction%20to%20Object-Relational%20Data%20Type%20Mappings%20(ELUG)#Object-Relational Data Type Structure Mapping|Object-Relational Data Type Structure Mapping]] | ::* [[Introduction%20to%20Object-Relational%20Data%20Type%20Mappings%20(ELUG)#Object-Relational Data Type Structure Mapping|Object-Relational Data Type Structure Mapping]] | ||
::* [[Introduction%20to%20Object-Relational%20Data%20Type%20Descriptors%20(ELUG)|Object-Relational Data Type Descriptors]] | ::* [[Introduction%20to%20Object-Relational%20Data%20Type%20Descriptors%20(ELUG)|Object-Relational Data Type Descriptors]] | ||
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| + | -- [[User:ben.gelernter.oracle.com|Ben Gelernter]] 4/28/11 | ||
| + | |||
| + | : More ELUG refs | ||
| + | : I removed the ELUG links from the final section | ||
| + | ::==Using Structure Converters to Configure Mappings== | ||
| + | |||
| + | ::In EclipseLink, a <tt>DatabasePlatform</tt> (see [[Introduction%20to%20Data%20Access%20(ELUG)#Database Platforms|Database Platforms]]) holds a structure converter. An <tt>org.eclipse.persistence.database.platform.converters.StructConverter</tt> affects all objects of a particular type read into the <tt>Session</tt> that has that <tt>DatabasePlatform</tt>. This prevents you from configuring the <tt>StructConverter</tt> on a mapping-by-mapping basis. To configure mappings that use the <tt>StructConverter</tt>, you call their <tt>setFieldType(java.sql.Types.STRUCT)</tt> method. You must call this method on all mappings that the <tt>StructConverter</tt> will affect – if you do not call it, errors might occur. | ||
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| + | ::The JPA specification requires all <tt>@Basic</tt> mappings (see [[Introduction%20to%20EclipseLink%20JPA%20(ELUG)#@Basic|@Basic]]) that map to a non-primitive or a non-primitive-wrapper type have a serialized converter added to them. This enables certain <tt>STRUCT</tt> types to map to a field without serialization. | ||
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| + | ::You can use the existing <tt>[[#How to Use the @Convert Annotation|@Convert]]</tt> annotation with its <tt>value</tt> attribute set to the <tt>StructConverter</tt> name – in this case, EclipseLink will apply appropriate settings to the mapping. This setting will be required on all mappings that use a type for which a <tt>StructConverter</tt> has been defined. Failing to configure the mapping with the <tt>@Convert</tt> will cause an error. | ||
Revision as of 14:36, 2 May 2011
-- Ben Gelernter 4/28/11
- ELUG ref
- I removed this reference that possibly is to ELUG. It currently xrefs a nonexistent target on this page. I suspect is used to be to a section in ELUG.
- Return here to see if this information needs to be brought forward into this doc.
- Note: You can also configure structure converters in a sessions.xml file (see What You May Need to Know About EclipseLink JPA Overriding Mechanisms).
-- Ben Gelernter 4/28/11
- ELUG ref
- I also removed these references to ELUG. Return here to see if this information needs to be brought forward into this doc.
- For more information, see the following:
-- Ben Gelernter 4/28/11
- More ELUG refs
- I removed the ELUG links from the final section
- ==Using Structure Converters to Configure Mappings==
- In EclipseLink, a DatabasePlatform (see Database Platforms) holds a structure converter. An org.eclipse.persistence.database.platform.converters.StructConverter affects all objects of a particular type read into the Session that has that DatabasePlatform. This prevents you from configuring the StructConverter on a mapping-by-mapping basis. To configure mappings that use the StructConverter, you call their setFieldType(java.sql.Types.STRUCT) method. You must call this method on all mappings that the StructConverter will affect – if you do not call it, errors might occur.
- The JPA specification requires all @Basic mappings (see @Basic) that map to a non-primitive or a non-primitive-wrapper type have a serialized converter added to them. This enables certain STRUCT types to map to a field without serialization.
- You can use the existing @Convert annotation with its value attribute set to the StructConverter name – in this case, EclipseLink will apply appropriate settings to the mapping. This setting will be required on all mappings that use a type for which a StructConverter has been defined. Failing to configure the mapping with the @Convert will cause an error.