How to deal with m2m relationship(posts and tags) by doctrine(in symfony)?

Question

posts and tags have a many-to-many relationship(pretty much like stackoverflow),so the code to do it without an ORM should be:

$dml = "insert into posts(title,body,created) value($title,'{$_POST['post-text']}',now())";
mysql_query($dml,$con);
$pid = mysql_insert_id($con);
//deal with tags

if(isset($_POST['tagnames']))
{
 $tags = preg_split('/\s+/',trim($_POST['tagnames']));
 $list = "('".implode("',1),('", $tags)."',1)";
 $dml = "insert into tags(name,count) values $list on duplicate key update count=count+1";
 mysql_query($dml,$con);
 $list = "('" . implode("','", $tags) . "')";
 $dml = "insert into post_tags(pid,tagId) select $pid,id from tags where name in $list";
 mysql_query($dml,$con);
}

How to do it with by doctrine?

Suppose that the related classes are already generated from schemas

The difficulty lies in the on duplicate key update part.

To step further,it can be more difficult to handle when someone is editing the posts...

Answer 1

Instead of managing this relationship yourself you might want to consider using sfDoctrineActAsTaggablePlugin, which will probably make your life easier.

Answer 2

Well, for me it looks pretty easy.

$post = new Post();
$tags = Doctrine_Query::create()->from('Tags t')->whereIn('t.name', $_POST['tags'])->execute();
foreach ($tags as $tag) $post->link($tag->get('id'));
$post->save();

Why not read manual first? Also please consider to generate a module with symfony doctrine:generate-module post Post and carefully read generated code.