Laravel，四种模特关系

Question

I have four models: Animal(which can only be "dog" or "cat"), Category, Breed and Post.

Table data:

Animal: - id - name

Category: - id - name - animal_id

Breed: - id - name - category_id

Post: - id - breed_id

What I need is to get all Posts that are about dogs. Have any ideas?

Update: My models:

class Animal extends Model
{

    public function categories()
    {
        return $this->hasMany(Category::class)->orderBy('name', 'ASC');
    }
}

class Category extends Model
{

    public function animal()
    {
        return $this->belongsTo(Animal::class);
    }

    public function breeds()
    {
        $this->hasMany(Breed::class)->orderBy('name', 'ASC');
    }
}

class Breed extends Model
{

    public function category()
    {
        return $this->belongsTo(Category::class);
    }

    public function posts()
    {
        return $this->hasMany(Posts::class);
    }
}

class Posts extends Model
{

    public function breed()
    {
        return $this->belongsTo(Breed::class);
    }

}

Answer 1

First of all you need to properly set up the relations in the eloquent models, here is an example of code,

For Post Eloquent Model And post must have the column animal_id

public function animal(){

    return $this->belongsTo(Animal::class);
}

Then you have to query like

$posts = Post::whereHas('animal',function($q){
    return $q->where('name','dog');});

After that you will get the posts which belongs to animal data where animal name is dog. And if you want to query with your current database structure that is not recommended because of complex and long query.