[ http://jira.jboss.com/jira/browse/JBAS-296?page=history ]
Scott M Stark closed JBAS-296:
------------------------------
Resolution: Out of Date
> is (not) null expression very limited
> -------------------------------------
>
> Key: JBAS-296
> URL: http://jira.jboss.com/jira/browse/JBAS-296
> Project: JBoss Application Server
> Type: Feature Request
> Components: CMP service
> Reporter: SourceForge User
> Assignee: Scott M Stark
>
>
> SourceForge Submitter: tpolling .
> The EJB QL expression <some value> IS NULL respectively
> <some value> IS NOT NULL is very limited in both EJB QL
> (EJB spec 2.0) and as it seems also in the current
> JBossQL (I have checked version 3.0.3 and looked up the
> current grammar file in the CVS repository).
> In particular, with EJB QL 2.0 and JBossQL, it is not
> possible to have null checks of input parameter, e.g.
> <query>
> <query-method>
> <method-name>findByName</method-name>
> <method-params>
> <method-param>java.lang.String</method-param>
> <method-param>java.lang.String</method-param>
> </method-params>
> </query-method>
> <jboss-ql> or <ejb-ql>
> select distinct object(p) from person as p where
> (?1 is null or p.first_name = ?1) and
> (?2 is null or p.name = ?2)
> </jboss-ql> resp. </ejb-ql>
> </query>
> where the find method is findByName(String firstName,
> String lastName) and has the semantics to match any
> field value if the argument if it is null.
> As for EJB QL v 2.0, the BNF grammar states that above
> is not possible:
> null_comparison_expression ::=
> single_valued_path_expression IS [NOT] NULL
> In the current JBossQLParser.jjt, it does not appear to
> be possible either:
> void NullComparisonExpression() #NullComparison :
> {}
> {
> SingleValuedPath() <IS> [<NOT> { jjtThis.not=true; }
> ] <NULL>
> }
> In EJB QL v 2.1, however, this restriction has been lifted:
> null_comparison_expression ::=
> {single_valued_path_expression | input_parameter} IS
> [NOT] NULL
> Now, it is arguable whether or not to allow any kind of
> single valued expression on the lhs of a IS [NOT] NULL
> expression. Clearly, statements like "'Some string' is
> null" would not make much sense semantically, however
> the above expression clearly is syntactically correct
> and can be reduced to return always false.
> In any case, omission of input parameter null checks is
> a severe restriction and forces potentially a fair
> amount of SQL queries to be coded in a non portable way.
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