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Design Specification: Join with ON clause

ER 367452

Document History

Date Author Version Description & Notes
22 December 2011 Gordon Yorke Initial Document created

Project overview

JPA 2.1 will add support for an ON clause within the JOIN clause of a Java Persistence Query. Support will be required for both JPQL and Criteria queries.

Concepts

Generally the only condition for a JOIN is that of the Foreign Key but the ON clause is intended to allow users to specify additional conditions for the JOIN.

eg: JPQL: SELECT s.name FROM Suppliers s LEFT JOIN s.products p ON p.status = 'inStock'

SQL: SELECT s.name FROM Suppliers s LEFT JOIN Products p ON s.id = p.supplierId AND p.status = 'inStock'

Requirements

Support the ON clause syntax of JPQL and the Criteria APIs

Design Constraints

Design / Functionality

Testing

API

GUI

Config files

Documentation

Work Required

  1. ON support in expression framework and JPQL
    Completed
  2. ON support in Criteria API
    approx 4 days
  3. Testing
    approx 3 days

Open Issues

This section lists the open issues that are still pending that must be decided prior to fully implementing this project's requirements.

Issue # Owner Description / Notes

Decisions

This section lists decisions made. These are intended to document the resolution of open issues or constraints added to the project that are important.

Issue # Description / Notes Decision

Future Considerations

During the research for this project the following items were identified as out of scope but are captured here as potential future enhancements. If agreed upon during the review process these should be logged in the bug system.