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https://issues.apache.org/jira/browse/OPENJPA-2086?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13166845#comment-13166845
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Karl PIhlblad commented on OPENJPA-2086:
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After some more investigation, it seems as if defaultNChar=true is not a good
strategy,
as it prevents Oracle's optimizer to use char/varchar indexes for nchar
parameters. Sigh...
Using @Column(columnDefinition) is then perhaps the only solution but that will
fail for constructs when comparing against functions:
eg; param = UPPER( col ), param = TRIM( col), etc.
However, unless a better solution is available, I think the conclusion is to
stick with columnDefinition, and convert the database character if neccesary...
Also, unfortunately, setObject() seems to be depending on what
PreparedStatement implementation is used. On WebSphere, WsPreparedStatment, or
perhaps the
WebSphere variant of OracleDictionary fails to get the 'fixed' semantics right.
Again, I suppose using the columnDefinition is the best shot...
> OracleDictionary setFixed and setFormOfUse(NCLOB) are not really doing what
> they should.
> -----------------------------------------------------------------------------------------
>
> Key: OPENJPA-2086
> URL: https://issues.apache.org/jira/browse/OPENJPA-2086
> Project: OpenJPA
> Issue Type: Bug
> Components: jdbc
> Affects Versions: 2.1.1, 2.2.0
> Environment: Oracle 9g, 10g and 11g
> Reporter: Karl PIhlblad
> Priority: Minor
> Labels: charset, nchar, openjpa, oracle
>
> The setString() method in the OracleDictionary tries to be smart and and look
> up the column type, and detect and apply nchar and/or fixed char semantics.
> However, I believe that the type information is normally not present for
> queries, and the functions are never called.
> That means that characters outside the database character set will be lost
> during translation, and that comparison on CHAR (fixed length) columns will
> not match if
> the arguments are not padded to the column length.
>
> I suggest that the special nchar handling is removed as it is not working
> properly. The only "reliable" option is to set the connection property
> oracle.jdbc.defaultNChar=true,
> as it would be neigh impossible to get this right in an automatic way.
> (Actually, the sensible option is to convert the database to AL32UTF8, and
> not use nchars at all since Oracles nchar handling seems to be problematic. )
> Further as the fixedString handling also does not work without type
> information, the dictionary could either always, or depending on a flag,
> call the setFixedChar() method, or just rely on the connection parameter
> "fixedString" (and use setObject), avoiding the complexity (and the cost of
> reflection calls) altogether.
>
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