Molten Monks,

Why is my code assigning the last-retrieved value to all elements in my hash?

I have a DB table, "booklist_table" that holds information about books to be published. As the book evolves, it can change title, and each time it does a new entry is made in the table with a unique update_id. The object of this script is to pull out all the LATEST titles of all books in the table and tell me the update_id's of those records. We start with a hash of book IDs, %booklist_1, where the keys are the IDs. 


$sql = "select update_id, title from booklist_table where (book_id = ?
+) order by update_id desc limit 1";
$sth = $dbh->prepare($sql) or die("Could not prepare!" . $dbh->errstr)
+;

foreach $book_id (keys %booklist_1) {

    $sth->execute($book_id) or die("Could not execute!" . $dbh->errstr
+);
    ($update_id, $title) = $sth->fetchrow_array();
    $booklist_1{$book_id}{'update_id'} = $update_id;
    $booklist_1{$book_id}{'title'} = $title;

    print "$book_id > $booklist_1{$book_id}{'update_id'}\n";
}
$sth->finish;

foreach $book_id (keys %booklist_1) {
    print "XXX $book_id > $booklist_1{$book_id}{'update_id'}\n";
}

[download]
The second loop is a temporary debugging tool to see how the booklist_1 hash was populated. The script gives me this output: 
100 > 456
101 > 753
102 > 489
103 > 259
XXX 100 > 259
XXX 101 > 259
XXX 102 > 259
XXX 103 > 259

[download]
That is, every $booklist_1{$book_id}{'update_id'} is being set to the last retrieved update_id.

What the heck?

Thanks.




Time flies like an arrow. Fruit flies like a banana.

In reply to Why is my code assigning the last-retrieved value to all elements in my hash? by punch_card_don

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