Notice: this Wiki will be going read only early in 2024 and edits will no longer be possible. Please see: https://gitlab.eclipse.org/eclipsefdn/helpdesk/-/wikis/Wiki-shutdown-plan for the plan.
EclipseLink/DesignDocs/251594
Query Hints
Document History
| Date | Author | Version Description & Notes |
|---|---|---|
| 2008-10-21 | James | 0.1 Draft |
Project overview
The complete functionality of the EclipseLink query framework needs to be exposed to JPA usage through query hints. Many of these hints have been requested by users, and some have been added, this attempt to provide the complete set and allow them to be documentation and names standardized.
Concepts
The query framework is the set of query classes defining EclipseLink's native query API.
Requirements
Support all relevant functionality of the EclipseLink native API query framework through JPA hints.
Functionality
List of new hints:
- eclipselink.query-results-cache
- eclipselink.query-results-cache.size
- eclipselink.query-results-cache.expiry
- eclipselink.query-results-cache.expiry-time-of-day
- eclipselink.maintain-cache
- eclipselink.session-name
- eclipselink.prepare
- eclipselink.jdbc.cache-statement
- eclipselink.sql.hint
- eclipselink.flush
- eclipselink.jdbc.native-connection
- eclipselink.sql
- eclipselink.call
- eclipselink.redirect
- eclipselink.expression
- eclipselink.query-type +support all query types
- eclipselink.result-type (Map, Array, Value, Values)
- eclipselink.cursor
- eclipselink.cursor.initial-size
- eclipselink.cursor.page-size
- eclipselink.cursor.scrollable
- eclipselink.cursor.scrollable.result-set-type (Forward, ForwardOnly, Unknown, Reverse,
ScrollInsensitive, ScrollSensitive)
- eclipselink.cursor.scrollable.result-set-concurrency (ReadOnly, Updatable)
- eclipselink.cursor.size-query
- eclipselink.fetch-group.name
- eclipselink.fetch-group.attribute
- eclipselink.fetch-group.default
- eclipselink.cache-usage.indirection-policy (Include, Exclude, ThrowException, Trigger)
- eclipselink.cache-usage +support modify queries
- eclipselink.exclusive-connection
- eclipselink.inheritance.outer-join
- eclipselink.history.as-of
- eclipselink.history.as-of-scn
- eclipselink.example-object
- eclipselink.example-object.policy
- eclipselink.hierarchical.connect-by
- eclipselink.hierarchical.start-with
- eclipselink.hierarchical.order-siblings
- eclipselink.jdbc.first-result
In addition the hint must not be stored as a Map, as some hints require multiple values (fetch, batch). The fetch hint should also allow usage of an outer-join.
i.e. "eclipselink.join-fetch"="emp.+address"
Documentation
New hints will require documentation in user docs.
Open Issues
| Issue # | Owner | Description / Notes |
|---|---|---|
| 01 | Should hierarchical be hints or JPQL? |
| Issue # | Description / Notes | Decision |
|---|