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Contents
Design Specification: JPQL Generic Function support
Document History
| Date | Author | Version Description & Notes |
|---|---|---|
| 08 November 2011 | Gordon Yorke | initial document creation |
| 11 April 2012 | James Sutherland | feature completed |
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 JPQL syntax. This feature will cover adding this support.
Concepts
May functions like 'UTC_DATE' are supported by databases but not provided within JPQL. This feature will provide the functionality 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
The functionality was added to the Criteria API in JPA 2.0
CriteriaBuilder.<T> Expression<T> function(String name, Class<T> type, Expression<?>... args);
Requirements
Implement support for 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.