Laravel 8: Undefined index - laravel

Question

I'm working on a questionnaire project and I ran into an error saying:
Undefined index: exams
This happened when I was trying to store responses to my database.
Here is my controller code:
public function store(Math $math)
{
$data = request()->validate([
'responses.*.answer_id' => 'required',
'responses.*.question_id' => 'required'
]);
$exam = $math->exams()->create($data['exams']);
$exam->examanswers()->createMany($data['examanswers']);
return 'Thank You';
}
Here is my exam model:
{
use HasFactory;
protected $fillable = ['exam'];
public function math()
{
return $this->belongsTo(Math::class);
}
public function examanswers()
{
return $this->hasMany(ExamAnswer::class);
}
}
question model:
{
use HasFactory;
protected $fillable = ['question'];
public function math()
{
return $this->belongsTo(Math::class);
}
public function answers()
{
return $this->hasMany(Answer::class);
}
}
Math model:
{
use HasFactory;
protected $fillable = [
'user_id', 'title', 'purpose', 'exam'
];
public function user()
{
return $this->belongsTo(User::class);
}
public function questions()
{
return $this->hasMany(Question::class);
}
public function exams()
{
return $this->hasMany(Exam::class);
}
}
Please help me look into it.

Answer 1

request()->validate(RULES) will return an array with all the existing rules' indexes. It will not return all data present, just what it is in the rules and present.
Read how $request->validate() works.
For example:
If you send home = 'Address', name = 'John' and email = 123, but your rules are:
$data = $request->validate([
'home' => 'required',
'name' => 'required',
]);
Then, if you want to use $data you would have (dd($data)):
$data['home']: Address
$data['name']: John
But email = 123 would not be present in $data.