> Subject: Help getting metadata from LISTFIELDS
> Date: Fri, 12 Mar 1999 14:10:40 +0000 (GMT)
> From: Paul Sharpe <paul@stripped>
> To: msql-mysql-modules@stripped
>
> This is Msql-Mysql-modules-1.21_15. Using a Mysql data source the
> following code returns a field count matching the number of fields in
> each table but no rows. How do I access the metadata I expected this
> 'SQL EXTENSION' to return?
>
> for my $table ( $dbh->tables ) {
> print "$table\n";
> my $sth = $dbh->prepare("LISTFIELDS $table") || die $dbh->errstr;
> my $rc = $sth->execute || die $dbh->errstr;
> print "rows = ",$sth->rows," fields = ",$sth->{NUM_OF_FIELDS},"\n";
> for my $row ( $sth->fetchrow_arrayref ) {
> print "\t@$row\n";
> }
> }
The LISTFIELDS instruction (which is internally mysql_list_fields, of
course)
does nothing more than returning an empty table. You can think of it as
being equivalent to
SELECT * FROM $table WHERE 1=0
So the number 0 is correct for the rows. What do you expect it to return?
If you want the number of rows from $table, use COUNT(*).
Bye,
Jochen
--
Jochen Wiedmann joe@stripped
"How could this be a problem in a country where +49 7123 14887
we have Intel and Microsoft?" (Al Gore, Vanity Fair,
January 1999 issue, talking about Y2K)
