Laravel 5数据透视表额外字段

Question

What I'm trying to do is when a new candidate is created an extra field is automatically populated in the joining pivot table with a random sting.

Here is my pivot table:

Result Table (pivot)

id  cert_number candidate_id    qualification_id
1   ?           17              2
2   ?           17              1
3   ?           57              1

So in my candidate controller I have:

public function store(CandidateRequest $request)
{
    $candidateInput = Input::get('candidates');


    foreach ($candidateInput as $candidate)
    {
        $candidate = Candidate::create($candidate);

        $candidate->centre()->attach(Auth::user()->centre);

        $qualification_id = $request->input('qualification_id');

        $candidate->qualification()->attach($qualification_id);

        $cert_number = Str::random(10);

        $candidate->qualification()->attach($cert_number);

    }

    return redirect('candidates');
}

It adds the centre_id and qualification_id perfectly but it won't pull though the random sting into the cert_nubmer field.

In my Candidate model I have

public function result()
{
    return $this->hasMany('App\Result')->withTimestamps();
}

public function qualification()
{
    return $this->belongsToMany('App\Qualification', 'Results', 'candidate_id', 'qualification_id')->withPivot('status','cert_number','partial_claim')->withTimestamps();
}

and in my result model:

public function candidate()
{
   return $this->belongsTo('App\Candidate')->withTimestamps();
}

public function qualification()
{
   return $this->belongsTo('App\Qualification');
}

Can anyone see where Im going wrong?

Thanks.

Answer 1

attach does not work like that.

Let me take out two lines of code:

$candidate->qualification()->attach($qualification_id);
$candidate->qualification()->attach($cert_number);

You are trying to add the $cert_number as a qualification_id, which is why it fails. When you do this, how is Laravel supposed to know that the second line ($cert_number) is an extra pivot column? It doesn't. You have two lines of code that are exactly the same so you can't expect Laravel to know that the second line should do something different.

When you want to insert extra data into other pivot columns, you need to pass them as an array in the second argument. Something like this:

$candidate->qualification()->attach($qualification_id, ['cert_number' => $cert_number]);