Table of Contents for

MySQL in a Nutshell, 2nd Edition

This function returns a reference to a place in memory containing a hash of keys and values for one row from the results of a statement handle. The optional argument of this method is to give the statement handle name attribute: NAME (the default), NAME_lc, or NAME_uc. See the end of this chapter for a description of these attributes. The name must be given within quotes if given as a string. Null values retrieved by this method are returned as undefined. An empty value is returned when there is an error or when there are no more rows remaining in the results set. Therefore, if used in a flow control statement such as while, the empty value returned will end the loop statement. Here is an example:

...
my $sql_stmnt = "SELECT title, author FROM books";
my $sth = $dbh->prepare($sql_stmnt);
$sth->execute();

while (my $book_ref = $sth->fetchrow_hashref('NAME_uc')) {
   print "$book_ref->{'TITLE'} by $book_ref->{'AUTHOR'} \n";
}

$sth->finish();

Notice that the name given here with this method instructs the hash to use all uppercase letters for the key names. Therefore, when calling the particular data, the column names are given in all uppercase letters. If no parameter was given, we could use the column names as they are in the table. The fetchrow_hashref() method is much simpler than fetchall_hashref(), but you can’t close the statement handle until you’re finished processing the results. Therefore, you may want to consider using fetchall_hashref() instead.