Laravel更新一对多关系

Question

I have two table the first is subjects table and the second is subjects_doctors table . The relationship here is One To Many .

Update method code:

public function update(Request $request, $id)
    {
        $this -> validate($request, [
            'name'          => 'required',
            'max_students'  => 'required',
            'doctors'       => 'required',
            'description'   => 'required'
        ]);

        $subject = Subject::find($id);
        $subject -> name            = $request -> name;
        $subject -> description     = $request -> description;
        $subject -> max_students    = $request -> max_students;
        $subject -> save();
//PROBLEM
        $y = Subject::where('id', $subject -> id) -> doctors() -> update(['doctor_id' => $request -> doctors]);


        Session::flash('success', 'Subject has been updated successfully!');
        return redirect() -> route('subjects.index');
    }

The $request variable contain an array that have all the updated doctors id .

For Example

I have in the subjects table that subject 1 HAVE 1 DOCTOR and I have updated it to SUBJECT 1 HAVE 2 DOCTORS .. How I do that?

I have everything in variables but I can't update them in the subjects_doctors table.

Answer 1

The problem has been solved by using the sync() function from Laravel. Thanks.

here is the code it may help

$subject = Subject::find($id);
    $subject -> name            = $request -> name;
    $subject -> description     = $request -> description;
    $subject -> max_students    = $request -> max_students;
    $subject -> save();

    $subject -> doctors() -> sync($request -> doctors);