RE: Checking NULL value...

Thanks, I figured it out - the server doesn't set the NULL indicator of the sqlvar structure after the fetch unless you allocate a short and put it in the structure. Also, if anyone is interested, the risnull() does not work correctly on char data types returned from the server using the sqlda structure. The value of the char returned if the column is NULL is '\\0' which is the same as if the value of the column was set to '\\0' - even though they are different on the server. Bryan Hughes Shutterfly.com -----Original Message----- From: William Rice [mailto:ricew@operamail.com] Sent: Sunday, May 07, 2000 7:58 AM To: Pacbell News; informix-list Subject: RE: Checking NULL value... I always used an INDICATOR for the column to find if it was NULL. Information on indicators should be in your esqlc manual Will >===== Original Message From "Pacbell News" <hughesb@pacbell.net> ===== >I am hoping someone can help me. My ESQL/C code is having difficulty >distiquishing between a column with a NULL value and a column = '\\0' (or "") >using a sqlda structure after a FETCH ... USING DESCRIPTOR ... > >I have correctly DESCRIBED the statement into the sqlda structure and >allocated the memory accordingly. I have the following table: > >CREATE TABLE test ( name char(16), value char(16) );> >INSERT INTO test ( name, value ) values ( "test", "" ); >INSERT INTO test ( name ) values ( "test1" );> >If I use dbaccess and do a SELECT * FROM test WHERE value IS NULL, the row >with name = "test1" is returned. > >In my ESQL/C code, immediately before the fetch sqlvar[...].sqlind is NULL >as well as immediately after for both rows. When I use the Informix library >call risnull(), it returns TRUE for both records. > >Why is dbaccess able to determine that one row is NULL and the other is a >single character string with a NULL value? > >Bryan Hughes >Shutterfly.com > >-- > >------------------------------------------------------------ >"A doctor can bury his mistakes but an architect can only >advise his client to plant vines." -- Frank Lloyd Wright ------------------------------------------------------------ This e-mail has been sent to you courtesy of OperaMail, as a free service from Opera Software, makers of the award-winning Web Browser, Opera. Visit us at http://www.opera.com/ or our portal at: http://www.myopera.com/ Your free e-mail account is waiting at: http://www.operamail.com/ ------------------------------------------------------------