Notice: This Wiki is now read only and edits are no longer possible. Please see: https://gitlab.eclipse.org/eclipsefdn/helpdesk/-/wikis/Wiki-shutdown-plan for the plan.
Difference between revisions of "EclipseLink/Development/DBWS/oNmMetadata"
< EclipseLink | Development | DBWS
(→OR new-format metadata requirements) |
(→OR new-format metadata requirements) |
||
| Line 24: | Line 24: | ||
* session-level settings: database platform information, container settings, etc. | * session-level settings: database platform information, container settings, etc. | ||
* session-level queries whose arguments use complex types (advanced JDBC types; PL/SQL records+collections) | * session-level queries whose arguments use complex types (advanced JDBC types; PL/SQL records+collections) | ||
| − | ** Struct | + | ** Struct and Array mappings ([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 ==== | ==== OXM new-format metadata requirements ==== | ||
Revision as of 11:31, 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.
OR new-format metadata requirements
- Direct mappings with sufficient attribute information to support the range of datatypes used by XML
- session-level settings: database platform information, container settings, etc.
- session-level queries whose arguments use complex types (advanced JDBC types; PL/SQL records+collections)
OXM new-format metadata requirements
- Direct mappings with sufficient attribute information to support the range of schema types used in XML
- Composite, CompositeCollection and DirectCollection mappings
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.