Connect 3 tables with 2 pivot tables

replied 9 years ago

Solution

What you need is a "has many through many" relationship but laravel doesn't support it.

Here is an old thread about it. http://laravel.io/forum/03-04-2014-hasmanythrough-with-many-to-many

There are some workarounds people have come up with and I can offer you another one which I think is pretty clean. It's a scope that has nested whereHas inside the model C

model C --

public function scopeHasAViaB($query, $ids) {
    if (empty($ids)) {
        return new \Illuminate\Database\Eloquent\Collection();
    }
    return $query->whereHas('b', function ($query) use ($ids) {
            $query->whereHas('a', function ($query) use ($ids) {
                $query->whereIn('id', $ids);
            });
        });
}

-- controller code --

  $modelAkeys = [1,2]
    $cc = ModelC::HasAViaB($modelAKeys)->paginate(10);

0

mattusik

replied 9 years ago

Thank you, It works like a charm, but it takes a lot of time in case of ~5 mil C rows.

0

frezno

replied 9 years ago

maybe you can modify your database structure. 3 tables with two pivot tables that's quite a complex structure.

0

rickshawhobo

replied 9 years ago

make sure all your foreign keys are indexed

0

staudenmeir

replied 6 years ago

I created a HasManyThrough relationship with support for BelongsToMany: Repository on GitHub

After the installation, you can use it like this:

class A extends Model {
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function c() {
        return $this->hasManyDeep(C::class, ['a_b', B::class, 'b_c']);
    }
}

0

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