Re: [Fwd: [PATCHES] Libpq support for precision and scale]
От | Bruce Momjian |
---|---|
Тема | Re: [Fwd: [PATCHES] Libpq support for precision and scale] |
Дата | |
Msg-id | 200202222334.g1MNYr607155@candle.pha.pa.us обсуждение исходный текст |
Ответ на | [Fwd: [PATCHES] Libpq support for precision and scale] (Fernando Nasser <fnasser@cygnus.com>) |
Список | pgsql-hackers |
Sorry, I see later comments questioning the patch. Please review and resubmit: http://candle.pha.pa.us/cgi-bin/pgpatches2 --------------------------------------------------------------------------- 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> -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 853-3000+ If your life is a hard drive, | 830 Blythe Avenue + Christ can be your backup. | Drexel Hill, Pennsylvania19026
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