如何在 laravel

Question

I have two tables departments and subjects. One department can have many subject, so it can be hasMany relationship. But when i call $subject->department()->save($department); it shows me the above error

MY department model

 protected $primaryKey='dept_id';
public function subjects()
{
    return $this->hasMany(Subject::class);
}

My subject Model

 protected $primaryKey='sub_id';
    public function department()
{
    return $this->belongsTo(Department::class);
}

And in my seedin i try this

$departments = array(
            array('name' => 'Bachelor of Business Administration'),
            array('name' => 'Bachelor of Computer Science and Engineering'),
            array('name' => 'Bachelor of Science in Civil Engineering'),
            array('name' => 'Bachelor of Science in Mechanical Engineering'),
            array('name' => 'Bachelor of Electrical & Electronics Engineering'),
            array('name' => 'Bachelor of Science in Nursing'),
            array('name' => 'Bachelor of Arts in Tourism and Hospitality Management'),
            array('name' => 'Bachelor of Science in Agriculture'),
            array('name' => 'Bachelor of Arts in Economics'),
        );
        Department::insert($departments);
        $subjects = array(
            array('name' => 'Software'),
            array('name' => 'Networking'),
        );
        $department=Department::where('name','Bachelor of Computer Science and Engineering')->first();
        $subject= Subject::insert($subjects);
        $subject->department()->save($department);

But i am always getting this error

Please help me to solve this problem I want to save all the subjects with their department ids.

Answer 1

As I can see you have used $subject = Subject::insert($subjects); which will return bool (0 or 1) as result of your insert function and you are trying to call the department() relation on that, thats why its giving error.

Answer 2

I see, the issue is with "::insert()" It will return boolean value as true/ false.

I would suggest to use create() instead of insert(). However with the use of create() you won't able to add multiple row at a single time, So there you should create a foreach loop on "$subjects" array and add it there one by one.

You need to change your approach, Here is the ref code.

$department = Department::where('name','Bachelor of Computer Science and Engineering')->first();

$subjects = array(
    array('name' => 'Software'),
    array('name' => 'Networking'),
);

foreach ($subjects as $subject) {
    $department->subjects()->create($subject);
}