Laravel 5 conditional many to many sync()

Question

I have a content model with many-to-many to categories and tags. Categories and tags are stored in the same table with a boolean tag flag:

category_id | name        | tag
1           | Products    | 0
2           | bestsellers | 1

My Content Model has conditional relationships so defined:

public function categories() {
    return $this->belongsToMany('Foothing\Content\Z\Entities\Category\Eloquent\Category', 'content_content_categories', 'cid', 'tid')->where('tag', false);
}

public function tags() {
    return $this->belongsToMany('Foothing\Content\Z\Entities\Category\Eloquent\Category', 'content_content_categories', 'cid', 'tid')->where('tag', true);
}

While the tag flag is working properly on read operations, i.e.

$categories = Content::find(1)->categories;
$tags= Content::find(1)->tags;

it is not working as expected in sync operations, infact the following code

$content->categories()->sync(1, 2, 3);

will sync the whole table, regardless of the tag flag: tags will be destroyed and my content will be related only to categories 1, 2, 3.

Is it there something bad with this approach?

Answer 1

I've come across the same situation like you, I play the trick like

// the 1st sync will remove all the relationship to the category table
$content->categories()->sync([1, 2, 3]);
// the 2nd sync is to extends the relationship from the 1st
$content->tags()->syncWithoutDetaching([4, 5, 6]);

Both are from same table, that means the id should be different. This should work fine for the problem