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Difference between revisions of "EclipseLink/DesignDocs/350843"

(Project overview)
(Concepts)
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== Concepts ==
 
== Concepts ==
May functions like 'UTC_DATE' are supported by databases but not provided with the JPQL syntax or the criteria API.  This feature will provide the APIs necessary to call a function by name using the keyword FUNCTION.  The syntax takes the form:
+
May functions like 'UTC_DATE' are supported by databases but not provided within the criteria API.  This feature will provide the APIs necessary to call a function by name using the keyword FUNCTION.  The syntax takes the form:
  
 
function_invocation::= FUNCTION(function_name {, function_arg}*)
 
function_invocation::= FUNCTION(function_name {, function_arg}*)

Revision as of 15:05, 20 March 2012

Design Specification: Generic Query function support

ER 350843

Document History

Date Author Version Description & Notes
08 November 2011 Gordon Yorke initial document creation

Project overview

The SQL spec and many databases have SQL functions that are not covered by the JPA specification. With the latest JPA specification the ability to call generic SQL functions will be added to the Criteria API. This feature will cover adding this support.

Concepts

May functions like 'UTC_DATE' are supported by databases but not provided within the criteria API. This feature will provide the APIs necessary to call a function by name using the keyword FUNCTION. The syntax takes the form:

function_invocation::= FUNCTION(function_name {, function_arg}*) function_arg ::=

                literal |
                state_field_path_expression |
                input_parameter |
                scalar_expression

and CriteriaBuilder.<T> Expression<T> function(String name, Class<T> type, Expression<?>... args);

Requirements

Implement support for the function() method and the FUNCTION keyword.

Design Constraints

Design / Functionality

Testing

API

GUI

Config files

Documentation

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.

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