> How can you
>
> if(update row fails because doesn't exist, ie. returns 0)then(insert row)
Depends on what interface you are using.
In perl DBI, the return value of the a $dbh->do("update...") should be
the nomber of rows inserted. Same with doing a sequence of
$sth=$dbh->prepare("updated...");
$rc=$sth->execute;
$rc will be the number of rows updated. Then just do the insert if $rc is 0.
In php, you use the function pg_NumRows.
In libpg, the number of rows is obtained from PGntuples after the update;
Karl