datamapper many to many

[eluser]bralens[/eluser]

Code:

$categories = new Category();
$categories->where('public', 1)->get();

$post = new Post();
$post->title = $this->input->post('title');
$post->save($categories->all);

This code check if in join_Categories_Posts table already exists relation, but don't make new one if there is no relation.