Relationships

Why Relationships Matter

Real databases are full of related data. A user has posts, a post has comments, a comment belongs to a user. Eloquent models these relationships as methods, making it easy to traverse your data without writing JOINs.

One-to-One: hasOne

A one-to-one relationship means one record is directly related to one other record. For example, a User has one Profile:

class User extends Model
{
    public function profile()
    {
        return $this->hasOne(Profile::class);
    }
}
    

Access it like a property:

$profile = $user->profile;
echo $profile->bio;
    

One-to-Many: hasMany

A user can have many posts. Define this relationship with hasMany:

class User extends Model
{
    public function posts()
    {
        return $this->hasMany(Post::class);
    }
}
    

Retrieve all posts for a user:

$posts = $user->posts;
foreach ($posts as $post) {
    echo $post->title;
}
    

Inverse: belongsTo

Every hasMany has an inverse. A Post belongs to a User:

class Post extends Model
{
    public function user()
    {
        return $this->belongsTo(User::class);
    }
}
    

Now you can access the user from a post:

echo $post->user->name;
    

Many-to-Many: belongsToMany

When both sides can have multiple records — like users and roles — use belongsToMany. This requires a pivot table:

class User extends Model
{
    public function roles()
    {
        return $this->belongsToMany(Role::class);
    }
}
    

Eloquent expects a role_user pivot table with user_id and role_id columns.

Through Relationships

Sometimes you need to access a distant relationship. A Country has many Posts through Users. Use hasManyThrough:

class Country extends Model
{
    public function posts()
    {
        return $this->hasManyThrough(Post::class, User::class);
    }
}
    

Now $country->posts gives you all posts from users in that country.