Re: [Fwd: [PATCHES] Libpq support for precision and scale] - Mailing list pgsql-hackers

Sorry, I see later comments questioning the patch.  Please review and
resubmit:
http://candle.pha.pa.us/cgi-bin/pgpatches2


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Fernando Nasser wrote:
> This is a patch that was posted some time ago to pgsql-patches and
> no one has commented on it.
> 
> It adds something that JDBC has that is not present in libpq (see below).
> Is it OK for inclusion?
> 
> Regards to all and thanks for your time,
> Fernando
> 
> 
> -------- Original Message --------
> From: Fernando Nasser <fnasser@redhat.com>
> Subject: [PATCHES] Libpq support for precision and scale
> To: pgsql-patches@postgresql.org
> 
> Some programs like utilities, IDEs, etc., frequently need to know the
> precision and scale of the result fields (columns).  Unfortunately
> libpq does not have such routines yet (JDBC does).
> 
> Liam and I created a few ones that do the trick, as inspired by the
> JDBC code. The functions are:
> 
> char *PQftypename(const PGresult *res, int field_num);
> 
> Returns the type name (not the name of the column, as PQfname do).
> 
> 
> int PQfprecision(const PGresult *res, int field_num);
> int PQfscale(const PGresult *res, int field_num);
> 
> Return Scale and Precision of the type respectively.
> 
> 
> Most programs won't need this information and may not be willing
> to pay the overhead for metadata retrieval. Thus, we added
> an alternative function to be used instead of PQexec if one
> wishes extra metadata to be retrieved along with the query
> results:
> 
> PGresult *PQexecIncludeMetadata(PGconn *conn, const char *query);
> 
> It provides the same functionality and it is used in exactly the
> same way as PQexec but it includes extra metadata about the result
> fields.  After this cal, it is possible to obtain the precision,
> scale and type name for each result field.
> 
> 
> The PQftypename function returns the internal PostgreSQL type name.
> As some programs may prefer something more user friendly than the
> internal type names, we've thrown in a conversion routine as well:
> 
> char *PQtypeint2ext(const char *intname);
> 
> This routine converts from the internal type name to a more user
> friendly type name convention.
> 
> 
> More details are in the patch to the SGML documentation that is 
> part of the patch (attached).
> 
> 
> --
> Liam Stewart <liams@redhat.com>
> Fernando Nasser <fnasser@redhat.com>

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