hasOne vs hasMany

 

hasOne

Used when one model owns one related record.

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

Database:

users
profiles
    user_id

Usage:

$user->profile;

hasMany

Used when one model owns multiple records.

public function orders()
{
    return $this->hasMany(Order::class);
}

Usage:

$user->orders;

Scenario

If a user has exactly one profile:

User -> Profile

use hasOne.

If a user can place hundreds of orders:

User -> Orders

use hasMany.