如何使用Eloquent和Laravel创建关注者关系？

Question

So, I'm trying to create a relationship where users can follow other users or follow categories. My intuition says that what I've done so far is not the right way of doing things. I'm especially confounded by how to create the follower - followee relationship.

TABLES:

Users

public function up()
    {
        Schema::create('users', function (Blueprint $table) {
            $table->increments('id');
            $table->string('email');
            $table->string('password');
            $table->string('first_name');
        });
    }

Categories

public function up()
    {
        Schema::create('categories', function (Blueprint $table) {
            $table->increments('id');
            $table->string('category');
        });
    }

Follows

public function up()
    {
        Schema::create('follows', function (Blueprint $table) {
            $table->increments('id');
            $table->integer('follower_id');
            $table->integer('followee_id')->nullable();
            $table->integer('category_id')->nullable();
        });
    }

MODELS:

User

class User extends Model implements Authenticatable 
{

    public function follows()
    {
        return $this->hasMany('App\Follow');
    }
}

Category

class Category extends Model
{

    public function follows()
    {
        return $this->hasMany('App\Follow');
    }
}

Follow

class Follow extends Model
{
    public function post()
    {
        return $this->belongsTo('App\User');
    }
    public function source()
    {
        return $this->belongsTo('App\Category');
    }
}

Answer 1

According to your scenario, it is recommended that you use Polymorphic Many To Many relationship.

Schema:

users
    id - integer
    ...

categories
    id - integer
    ...

followables
    user_id - integer
    followable_id - integer
    followable_type - string

Models:

User:

public function followers()
{
    return $this->morphToMany(User::class, 'followables');
}
public function following()
{
    return $this->morphedByMany(User::class, 'followables');
}

Category:

public function followers()
{
    return $this->morphToMany(User::class, 'followables');
}

Then you can create the relationship like:

When following an User:

$user->followers()->create(['user_id' => 12])

When following a Category:

$category->followers()->create(['user_id' => 25])

Hope it helps.