Save data with 3 relations eloquent - mysql

Question

I am trying to save data with eloquent relationship.
I have following three tables: User Table, Category Table and Post Table.
Post Table
Schema::create('posts', function (Blueprint $table) {
$table->increments('id');
$table->integer('category_id')->unsigned();
$table->integer('user_id')->unsigned();
$table->string('heading');
$table->timestamps();
$table->foreign('category_id')->references('id')->on('categories');
$table->foreign('user_id')->references('id')->on('users');
});
Relations:
Category:
public function posts() {
return $this->hasMany('App\Post');
}
Post:
public function user() {
return $this->belongsTo('App\User');
}
public function category() {
return $this->belongsTo('App\Category');
}
User:
public function posts($category) {
return $this->hasMany('App\Post');
}
My Problem is that, how can I save post just by passing the Heading in create function. I want to use the relationship. As an example I want to use this kind of code:
$data = ['heading' => $heading];
$user->posts()->category()->create($data);
Is this possible to do this kind of stuff ?
Or any another simple way to achieve this.
EDIT
I need to create post by using this kind of relationship.
As per the process:
user will fill up the form from which I will get the data along with
the category id.
Now I need to create data for that user related with the given category id.

Answer 1

It's because after you call posts() method you won't get to the model's relation (only the query builder) so you will not access category() relation method. It's because posts are one-to-many relation and you don';t know exacly which record you refer to create data.
EDIT
If you want to create new post entry the the best way to sole this is:
$data = ['heading' => $heading, 'category_id' => $putHereCategoryId];
$user->posts()->create($data);
You'll need to obtain somehow the id of the desire category for the new post's entry.