Re: AbstractJdbc2Array - another patch - Mailing list pgsql-jdbc

On Wed, Nov 21, 2007 at 05:49:28PM -0500, Kris Jurka wrote:
>
>
> On Tue, 30 Oct 2007, Marek Lewczuk wrote:
>
> >in the attachment you can find jdbc.patch (that includes patches for a few
> >classes). You will see that I've added base types array types and right
> >now Array implementation works as should (your last test case is working,
> >which means that when using Array.getResultSet() returns appropriate
> >Array.getBaseType() and Array.getBaseTypeName()). However those changes
> >are not enough, there has to be more to be done in order to provide
> >support for user defined types, but  I think that should be done later. I
> >also think that class TypeInfoCache must be absolutely rewritten, cause it
> >is not prepared for user defined types.
> >
>
> Attached is a revised version of your patch after I worked on it a bit.
> Things I've changed:
>
> 1) Looking up the array type for a base type by using typelem doesn't work
> because typelem is not unique.  Since no code was calling getPGTypeArray,
> I just removed this code.
>
> 2) Fixed driver code that was relying on the array return type in
> AbstractJdbc2DatabaseMetaData.
>
> 3) Fixed the regression tests and added new ones to verify that array
> handling works.
>
> 4) Changed Array.getResultSet to use generic coding rather than hardcoding
> type oids for each java.sql.Types value.  This allows getResultSet to be
> used on types that aren't known to the driver, like aclitem[].  You still
> can't call getArray on this type, but we're getting closer.
>
> 5) Array.getResultSet didn't respect index or offset parameters.
>
> 6) For TypeInfoCache I've added a new column to link the base and array
> types instead of duplicating the whole rows.
>
> 7) Code did not correctly handle a string value of NULL in arrays for 8.1
> and earlier server versions.
>
> So with these changes, I think the code is pretty much ready to go, with
> the exception of how multidimensional results are returned.  The way you
> wrap the arrays in Object[] makes it impossible to cast to things like
> Integer[][].  Also I think we should be able to return multidimensional
> arrays of primitive type if the "compatible" option is set to 8.2.  I
> think you should be using java.lang.reflect.Array#newInstance to create
> the arrays you are returning to get the correct type instead of building
> them up incrementally.
>
> Kris Jurka

Kris/Marek: I've attached a very small followup patch which addresses a
need I had: I was using java.sql.DatabaseMetaData's getColumns method to
attempt to get the COLUMN_SIZE attribute for a column of type "character
varying(255) []".  Without my patch (applied after Kris's patches) the
COLUMN_SIZE would be 2147483647, with the patch it would be 255.  I am
by no means a JDBC or Postgresql expert, so maybe I am way off base.
What do you think?

Eric.