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Difference between revisions of "EclipseLink/Development/DBWS/oNmMetadata"
< EclipseLink | Development | DBWS
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| − | == DBWS and new | + | == DBWS and new-format metadata == |
=== Issues Summary === | === Issues Summary === | ||
At some point in the future, DBWS will switch from using 'native' EclipseLink metadata (a.k.a. Project deployment xml) | At some point in the future, DBWS will switch from using 'native' EclipseLink metadata (a.k.a. Project deployment xml) | ||
| − | to using 'oxm' and 'orm' (a.k.a JPA-style) metadata formats. In addition to using the new metadata | + | to using 'oxm' and 'orm' (a.k.a JPA-style) metadata formats. In addition to using the new-format metadata, DBWS typically |
operates without persistent model classes; thus at runtime, a dynamic solution is required for the generation of | operates without persistent model classes; thus at runtime, a dynamic solution is required for the generation of | ||
persistent model classes. | persistent model classes. | ||
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=== General Solution === | === General Solution === | ||
Similar to the current DBWS support, the new-format metadata files will be produced at design time by a DBWS utility. | Similar to the current DBWS support, the new-format metadata files will be produced at design time by a DBWS utility. | ||
| − | Later DBWS will | + | Later DBWS will at runtime read-in the new-format metadata files, dynamically generate persistent model classes, |
| − | and realize | + | and realize an environment that bridges between representation in a relational database and in an XML document. |
| − | and in an XML document. | + | |
=== Requirements === | === Requirements === | ||
| − | * the 'oNm.xml' metadata must support the majority of EclipseLink features ( | + | * the new-format 'oNm.xml' metadata must support the majority of EclipseLink features (see below) |
| + | * as there are no persistent model classes on the classpath, processing the new-format metadata must use only simple scalar objects (Strings, booleans, numbers, etc.) for all capabilities and settings. | ||
| + | * an in-memory model of the new-format metadata can be read in from an file (or stream, URL, etc.) without persistent model classes on the classpath. | ||
| + | * an in-memory model of the new-format metadat can be serialized to a file (or stream, URL, etc.) without persistent model classes on the classpath. | ||
| + | * an in-memory model of the new-format metadata can be realized into runtime artifacts, including generating persistent model classes. | ||
| + | * generated persistent model classes must work when mapped simultaneously by both an OR and OX metadata model. <br/> i.e. an instance of a generated class must support the following: a row is retrieved from the database, built into an instance object and that very same object is serialized to XML - and vice-versa. | ||
| + | |||
| + | ==== ORM new-format metadata requirements ==== | ||
** NB: currently, new metadata formats do not support all EclipseLink features, not even all features required by DBWS (e.g. [https://bugs.eclipse.org/bugs/show_bug.cgi?id=211299 211299], [https://bugs.eclipse.org/bugs/show_bug.cgi?id=221876 221876]) | ** NB: currently, new metadata formats do not support all EclipseLink features, not even all features required by DBWS (e.g. [https://bugs.eclipse.org/bugs/show_bug.cgi?id=211299 211299], [https://bugs.eclipse.org/bugs/show_bug.cgi?id=221876 221876]) | ||
| − | + | ||
| − | + | ==== OXM new-format metadata requirements ==== | |
| − | + | ||
| − | + | ||
| − | + | ||
| − | + | ||
| − | + | ||
=== Open Issues === | === Open Issues === | ||
| + | * there are multiple solutions for dynamic generation of persistent model classes (SDO - <code>o.e.p.sdo.helper.DynamicClassWriter</code>; DBWS - <code>o.e.p.internal.dynamicpersist.BaseEntityClassLoader</code>). A separate functional spec should be created to examine the requirements and work required to refactor the multiple solutions into a common solution. | ||
=== Work Required === | === Work Required === | ||
Revision as of 11:12, 4 June 2009
Contents
DBWS and new-format metadata
Issues Summary
At some point in the future, DBWS will switch from using 'native' EclipseLink metadata (a.k.a. Project deployment xml) to using 'oxm' and 'orm' (a.k.a JPA-style) metadata formats. In addition to using the new-format metadata, DBWS typically operates without persistent model classes; thus at runtime, a dynamic solution is required for the generation of persistent model classes.
General Solution
Similar to the current DBWS support, the new-format metadata files will be produced at design time by a DBWS utility. Later DBWS will at runtime read-in the new-format metadata files, dynamically generate persistent model classes, and realize an environment that bridges between representation in a relational database and in an XML document.
Requirements
- the new-format 'oNm.xml' metadata must support the majority of EclipseLink features (see below)
- as there are no persistent model classes on the classpath, processing the new-format metadata must use only simple scalar objects (Strings, booleans, numbers, etc.) for all capabilities and settings.
- an in-memory model of the new-format metadata can be read in from an file (or stream, URL, etc.) without persistent model classes on the classpath.
- an in-memory model of the new-format metadat can be serialized to a file (or stream, URL, etc.) without persistent model classes on the classpath.
- an in-memory model of the new-format metadata can be realized into runtime artifacts, including generating persistent model classes.
- generated persistent model classes must work when mapped simultaneously by both an OR and OX metadata model.
i.e. an instance of a generated class must support the following: a row is retrieved from the database, built into an instance object and that very same object is serialized to XML - and vice-versa.
ORM new-format metadata requirements
OXM new-format metadata requirements
Open Issues
- there are multiple solutions for dynamic generation of persistent model classes (SDO -
o.e.p.sdo.helper.DynamicClassWriter; DBWS -o.e.p.internal.dynamicpersist.BaseEntityClassLoader). A separate functional spec should be created to examine the requirements and work required to refactor the multiple solutions into a common solution.