Re: DatabaseMetaData.getTables problem

From: Kris Jurka <books(at)ejurka(dot)com>
To: Barry Lind <blind(at)xythos(dot)com>
Cc: snpe <snpe(at)snpe(dot)co(dot)yu>, <pgsql-jdbc(at)postgresql(dot)org>
Subject: Re: DatabaseMetaData.getTables problem
Date: 2002-11-08 18:34:04
Message-ID: Pine.LNX.4.33.0211081325320.14247-100000@leary.csoft.net
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The problem is that the join to retrieve the table's comment from
pg_description is not properly constrained. A table's comment is
stored in pg_description with the objoid of the table's pg_class
oid and objsubid = 0. A table's column's comments are stored with the
table's pg_class oid and objsubid of pg_attribute.attnum. If any column
in the table has a comment then the query will not work properly
(retrieving extra rows).

Kris Jurka

On Fri, 8 Nov 2002, Barry Lind wrote:

> Can you also submit a test case? I would like to add a regression test
> that tests for the problem being fixed here. (which I don't understand
> entirely)
>
> thanks,
> --Barry
>
>
> snpe wrote:
> > Hello,
> > I am playing with DatabaseMetaData.getTables
> > I call getTables(null,null,"TABELA",null)
> >
> > ResultSet get (number of column of TABELA)+ 1 rows
> >
> > Patch for this problem is :
> > ---
> > /u2/postgrescvs/pgsql/src/interfaces/jdbc/org/postgresql/jdbc1/AbstractJdbc1DatabaseMetaData.java
> > 2002-11-04 12:03:04.000000000 +0000
> > +++ org/postgresql/jdbc1/AbstractJdbc1DatabaseMetaData.java 2002-11-07
> > 22:11:11.000000000 +0000
> > @@ -1988,7 +1988,7 @@
> > " END "+
> > " AS TABLE_TYPE, d.description AS REMARKS "+
> > " FROM pg_catalog.pg_namespace n, pg_catalog.pg_class c "+
> > - " LEFT JOIN pg_catalog.pg_description d ON (c.oid = d.objoid) "+
> > + " LEFT JOIN pg_catalog.pg_description d ON (c.oid = d.objoid and
> > d.objsubid = 0) "+
> > " LEFT JOIN pg_catalog.pg_class dc ON (d.classoid=dc.oid AND
> > dc.relname='pg_class') "+
> > " LEFT JOIN pg_catalog.pg_namespace dn ON (dn.oid=dc.relnamespace AND
> > dn.nspname='pg_catalog') "+
> > " WHERE c.relnamespace = n.oid ";
> >
> >
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> >
>
>
>
>
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