Help me remove mysql_insert_id - php

Question

Got three tables (blogs, tags, and blogtags) all AI and ID set to primary key. I'm making a tagging system to keep track of my sites (localhost). The code below is sort of working, but mysql_insert_id just doesn't seem reliable enough since I get some duplicate rows and the occasional 0 value in it.
/// inserts the blog into blog table.
$insert = mysql_query("INSERT INTO blogs (id, url, user, pass, dname, islocal, cat2post) VALUES ('', '$blog', '$bloguser', '$blogpassword', '','NO','$_POST[cat2blog]')")or die( 'Error: ' . mysql_error());
$taggit1 = mysql_insert_id();
$page->content .= "<p class=\"alert\">Success - External blog Added!</p>";
/// let's see what tags we have and explode them.
//$tags = $_POST['tags'] which is an array of words seperated by comma
$tags = 'fishing';
$pieces = explode(",", $tags);
/// go through the tags and add to tags table if needed.
foreach ($pieces as $l){
$l = trim($l);
$query = "SELECT id FROM tags WHERE tag = '$l'";
$result = mysql_query($query) or die( "Error: " . mysql_error() . " in query $query");
$row = mysql_fetch_array($result);
$taggit2 = $row[0];
if ($taggit2 == '') {
$insert2 = mysql_query("INSERT INTO tags (id, tag) VALUES ('','$l')")or die( 'Error: ' . mysql_error());
$taggit2 = mysql_insert_id();
$page->content .= "<p class=\"alert\">This tag didn't exist - so I inserted a new tag</p>";
}
/// for each tag we have, let's insert the blogstags table so we can reference which blog goes to which tag. Blogstags_id should map to the id of the blog.
$insert3 = mysql_query("INSERT INTO blogstags (id, tag_id, blogstags_id) VALUES ('','$taggit2','$taggit1')")or die( 'Error: ' . mysql_error());
}
Guess I need a different solution than mysql_insert_id - ideas? Suggestions?
As requested table structures:
CREATE TABLE IF NOT EXISTS `blogs` (
`id` int(11) NOT NULL auto_increment,
`url` text NOT NULL,
`user` text NOT NULL,
`pass` text NOT NULL,
`dname` text NOT NULL,
`islocal` varchar(3) NOT NULL,
`cat2post` int(11) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=12 ;
CREATE TABLE IF NOT EXISTS `blogstags` (
`id` int(11) NOT NULL auto_increment,
`tag_id` int(11) NOT NULL,
`blogstags_id` int(11) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=5 ;
CREATE TABLE IF NOT EXISTS `tags` (
`id` int(11) NOT NULL auto_increment,
`tag` text NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=7 ;

Answer 1

mysql_insert_id() is working fine. The problem could be that you are using persistant connections. With persistant connections, all kinds of funky concurrency issues can happen. Don't use them unless you really, really have to.

Answer 2

Two options - you could switch to PostgreSQL which allows you to return an auto_incremented ID as part of the insert query.
Or, if you are sticking with MySQL, you can use the MySQL LAST_INSERT_ID() function -