JPOX doesnt support queries selecting just a parameter

• Key: JDO-274
• Type: Bug
• Status: Resolved
• Resolution: Fixed
• Priority: Minor
• Assignee: Unassigned
• Reporter: Andy Jefferson
• Component/s: tck2

Description

When a JDOQL query selects just a parameter, JPOX has a SELECT statement with no columns selected resulting in a JDOUserException being thrown. This is demonstrated on TCK test
org.apache.jdo.tck.query.result.ResultExpressions.testParameter

[It has to be questioned why someone would want to create a JDOQL query of this form, since they supply the value of the parameter in the first place ;-)]

Comments

[Erik Bengtson]

1. The test should be extended to set values of different types. The basics Null, String and Long values, a non persistent object as parameter, which would make difficult to execute the query, and last, the test should also set a detached instance as parameter.

2. I agree with the expected result, but someone could ask why.

In SQL: SELECT literal value from TABLE WHERE condition, if condition evaluates to true, the literal is only one time in the result.

In JDOQL, that is not the case, so if condition evaluates to true, it will return N times the literal for N instances that evaluated to true. Of course, if DISTINCT keyword it turns to return 1 instance.

[Erik Bengtson]

fixed in JPOX