Re: have you feel anything when you read this ? - Mailing list pgsql-sql

Stephan Szabo wrote:
> On Tue, 4 Apr 2006, Eugene E. wrote:
> 
> 
>>Stephan Szabo wrote:
>>
>>>On Fri, 31 Mar 2006, Eugene E. wrote:
>>>
>>>
>>>
>>>>Peter Eisentraut wrote:
>>>>
>>>>
>>>>>Eugene E. wrote:
>>>>>
>>>>>
>>>>>
>>>>>>the problem is: you'll get this four byte sequence '\000' _instead_
>>>>>>of NUL-byte anyway.
>>>>>
>>>>>
>>>>>What you seem to be missing is that PostgreSQL data can be represented
>>>>>in textual and in binary form.  What you in psql is the textual form.
>>>>>If you want the binary form you need to select it.  Then you can pass
>>>>>the exact bytes back and forth.
>>>>
>>>>your sentence is not true.
>>>>I can not select exact bytes even if i use BYTEA type
>>>
>>>
>>>No, that is still using the textual form.  If you use PQexecParams and set
>>>the last argument to show you want binary data, you should get binary
>>>data.

ok
then i am using PQexecParams

the following tiny program shows a wonderful lameness...

#include <stdlib.h>
#include <stdio.h>
#include "libpq-fe.h"



int
main (void) {  PGconn   * conn;  PGresult * res;  char     * val;  char     *   l;  int        len;


  conn = PQconnectdb("user=scott password=tiger name=test_db");
  PQexec(conn, "CREATE TABLE t (a BYTEA)");  PQexec(conn, "INSERT INTO t VALUES ('ab\\\\000cd')");

  res = PQexecParams(conn, "SELECT a,length(a) FROM t", 0, NULL, NULL, 
NULL,  NULL, 1);  val = PQgetvalue(res,0,0);  l   = PQgetvalue(res,0,1);  len = PQgetlength(res,0,0);
printf("what_we_retrive='screened'its_value_length=%i but 
 
orig_length=%s\n",len,l);
  PQclear(res);  PQfinish(conn);
  return 0; }