From: Andrew C.R. Martin <a.c.r.martin@reading.ac.uk>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: interfaces@postgreSQL.org
Cc: docs@postgreSQL.org
Cc: hackers@postgreSQL.org
Subject: Re: [HACKERS] Re: Bugs: Programming Language Functions
Date: Tue, 11 Apr 2000 18:04:17 +0100
Message-ID: <00041118092100.28482@sapc13.rdg.ac.uk> (raw)
References: <1291.955469139@sss.pgh.pa.us>
On Tue, 11 Apr 2000, Tom Lane wrote:
> "Andrew C.R. Martin" <a.c.r.martin@reading.ac.uk> writes:
> > My own particular problem simply pulls out an integer and a (text *)
> > from a varchar. It then goes away and does some calculations based on
> > these values and another external file (in fact it does a system() to
> > run an external program which does these calculations). It then build
> > a 'text' structure containing the result.
>
> Hm. I'm not too clear on why that would need to worry about either
> TupleTableSlot or GetAttributeByName ... shouldn't it be a simple
> function consuming a text Datum and producing another?
Errrmmm, just following the instructions in the docs:
Programmer's Manual, Chapter 4. Extensing SQL: Functins (page x414.htm), under
the C examples.
My function looks something like:
text *mppfunc(TUPLE tuple)
{
text *attrib;
int resnum;
bool isnull;
char my_result[400];
if(((attrib = (text *)GetAttributeByName(tuple, "substitution", &isnull))
==NULL) || isnull)
return(pg_text("Invalid1"));
strncpy(newres, VARDATA(attrib), 40);
resnum = (int)GetAttributeByName(tuple, "codon", &isnull);
if(isnull)
return(pg_text("Invalid3"));
/* Do some stuff here putting a result string in my_result */
return(pg_text(my_result));
}
pg_text() is a little function to put a string into a PostgreSQL text data type.
Are you suggesting there is now an undocumented(?) easier way of doing this???
Best wishes,
Andrew
--
Dr. Andrew C.R. Martin EMail: a.c.r.martin@reading.ac.uk (work)
Lecturer in Bioinformatics andrew@stagleys.demon.co.uk (home)
University of Reading
Tel.: +44 (0)118 987 5123x7022 Fax: +44 (0)118 931 0180
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To: pgsql-interfaces@postgresql.org
Cc: a.c.r.martin@reading.ac.uk, tgl@sss.pgh.pa.us, interfaces@postgreSQL.org, docs@postgreSQL.org, hackers@postgreSQL.org
Subject: Re: [HACKERS] Re: Bugs: Programming Language Functions
In-Reply-To: <00041118092100.28482@sapc13.rdg.ac.uk>
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