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Date: Mon, 13 Feb 1995 15:18:17 -0500 (EST)
From: Robert.Patrick@cs.cmu.edu
To: postgres@postgres.Berkeley.EDU, Pconrad@eecis.udel.EDU
Subject: Re: Utility for tab_separated_text
CC: pconrad@eecis.udel.EDU
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Excerpts from internet.postgres: 12-Feb-95 Utility for
tab_separated_text Pconrad@eecis.udel.edu (1682)

>    I am working on a project where I will have a need for a utility
> that will take an arbitrary Postquel query and return the result as
> tab separated text, suitable for importing into (for example) a
> spreadsheet. 

Here's a somewhat crude example (please note that I am not being very
rigorous about error checking).

#include <tmp/libpq.h>
#include <stdio.h>
#include <string.h>

int main(int argc, char *argv[])
{
    int i, j, ncols, nrows;
    char *dbname, query[256]; 
    char *retval, *pstring;
    PortalBuffer *pbuf;

    dbname = argv[0];
    sprintf(query, "retrieve (EMP.all) where EMP.name = \"bob\");

    PQsetdb(dbname);
    pstring= PQexec(query);
    pbuf = PQparray(&(pstring[1]));
    ncols = PQnfieldsGroup(pbuf, 0);
    nrows = PQntuplesGroup(pbuf, 0);

    /* Put the code for opening the file here */

    for (i = 0; i < nrows; i++) {
        char tmpbuf[4096];
        int idx;

        idx = 0;
        for (j = 0; j < ncols; j++) {
            retval = PQgetvalue(pbuf, i, j);
	    sprintf (&(tmpbuf[idx]), "%s\t", retval);
             idx += strlen(retval) + 1;
        }
        tmpbuf[idx-1] = '\n';   /* overwriting final tab */

/* Put code for writing tmpbuf to the file */  
    }
/* Close the file */
    PQfinish();
    return(0);
}

I may have overlooked something but you should get the general idea of
how to do it.

Robert

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