如何在Laravel 5中链接递归数据结构？

Question

I'm making a model that has a recursive structure as seen below. the Concept model can have parent and child concepts, and the model works as expected. My problem is with implementing a page for adding links between two concepts.

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Concept extends Model
{
    //
    public function parentConcepts()
    {
        return $this->belongsToMany('App\Models\Concept','concept_concept','parent_concept_id','child_concept_id');
    }
    public function childConcepts()
    {
        return $this->belongsToMany('App\Models\Concept','concept_concept','child_concept_id','parent_concept_id');
    }
    public function processes()
    {
        return $this->hasMany('App\Models\Process');
    }
}

How would I go about doing that, exactly? Would I utilize the pivot attribute in the model, or would i create a new model and controller for the concept_concept table? any help would be very appreciated!

Answer 1

Creating a new function in the controller that utilizes the attach() function is the key to this solution.

public function storeChildLink(Request $request)
{
    //get the parent concept id
    $concept = Concept::find($request->input('parentConceptId'));
    //attach the child concept
    $concept->childConcepts()->attach($request->input('childConceptId'));

    $concept->save();

    return redirect()->route('concept.show', ['id' => $request['parentConceptId']])->with('status', 'Child Concept Successfully Linked');
}

public function storeParentLink(Request $request)
{
    //get the child concept id
    $concept = Concept::find($request->input('childConceptId'));
    //attach the parent concept
    $concept->parentConcepts()->attach($request->input('parentConceptId'));

    $concept->save();

    return redirect()->route('concept.show', ['id' => $request['childConceptId']])->with('status', 'Parent Concept Successfully Linked');
}