Laravel - Eloquent Relationship hasMany but also hasOne? - laravel

Question

I've been all over the web and struggling with this for around 2 hours.
I have a USER model, a RUN model and a TIME model.
In the real world the user is in a race and gets their time entered in the database along with a USER_id and a RUN_id.
A user should only be able to have one row in the TIMES table for each RUN_id - if that makes sense!
Is this something I need to manage at the controller level? Or is there a relationship I can setup to ensure that a duplicate entry of this style can not enter the database?
Database structure at present:
USERS:
name
RUNS:
name
TIMES:
time
user_id
run_id
The Models:
USER:
public function times()
{
return $this->hasMany(Time::class);
}
RUN:
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
class Run extends Model
{
public function user()
{
return $this->belongsTo(User::class);
}
public function times()
{
return $this->hasMany(Time::class);
}
}
TIME:
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
class Time extends Model
{
public function user()
{
return $this->belongsTo(User::class);
}
public function run()
{
return $this->belongsTo(Run::class);
}
}

Answer 1

You can add a unique key constraint on the times table to enforce unique combinations of user_id and run_id
$table->unique(['user_id, 'run_id']);
To validate uniqueness at the application level, we can also add a constraint to the form validation. Assuming that you are passing both user_id and run_id in the request to create a new time, you can add the following to a form request
/**
* Get the validation rules that apply to the request.
*
* #return array
*/
public function rules()
{
return [
'user_id' => Rule::unique('times')->where('run_id', $this->input('run_id'))
];
}
public function messages()
{
return [
'user_id.unique' => 'A user may only have 1 time entry per Run'
];
}
This will enforce the user_id is unique in the times table, filtered by that run id. The messages function also returns a more useful error message, since "user_id must be unique" is unhelpful in this situation.

Answer 2

This answer should supplement the accepted answer. You should still define the pair of user_id,run_id as a unique key.
However, in your case user and run have an N-N relationship with times as a pivot table. You should code it as such.
User
public function runs()
{
return $this->belongsToMany(Run::class, 'times')->withPivot('time');;
}
Run:
public function users()
{
return $this->belongsToMany(User::class, 'times')->withPivot('time');
}
Then you can retrieve them as:
$runs = User::find($userId)->runs; // Collection of all runs a user participated in
// $runs[X]->pivot->time has the time
You can check the documentation for more info