I would like to know how to pass an argument to a model relationship function. Just to be clear, I'm NOT talking about the query callback.
Consider a model like so:
class UserRelationships extends Model
{
// other stuff
// dynamic scope:
/**
* Scope a query to only include users of a given type.
*
* @param \Illuminate\Database\Eloquent\Builder $query
* @param mixed $type
* @return \Illuminate\Database\Eloquent\Builder
*/
// $relationships = UserRelationships::at( Carbon::parse('2022-10-10') )->get();
public function scopeAt($query, Carbon $date)
{
return $query->where('superseded_at', '>', $date )
->where('created_at', '<=', $date );
}
}
And a related model featuring the following relationships:
class User extends Authenticatable
{
public function progenial_relation(Carbon $date=null) // returns this user record in the userRelationships table, which can be used to retrieve this users parent (directly lookup the sponsor_id)
// when eager loading, this is useful for getting all users whose parent is x, hence the name
{
return $this->hasOne(UserRelationships::class, 'user_id', 'id')
->at( @$date ?: Carbon::now() ) // local dynamic scope in userRelationships
->orderByDesc('created_at')
->limit(1);
}
public function parental_relation(Carbon $date=null) // returns records from the userRelationships table, of all the users which refer to this user as their sponsor
// when eager loading, this is useful for getting the user whose child is x, hence the name
{
return $this->hasMany(UserRelationships::class, 'sponsor_id', 'id')
->at( @$date ?: Carbon::now() ); // local dynamic scope in userRelationships
}
}
As you can see my relationships accept an argument (the date).
Now, if you wanted to use those relationships straightforwardly like so, there's no issues:
$date = Carbon\Carbon::parse('2022-06-01');
$relations_at_date = User::find(1)->parental_relation( $date )->get();
But what happens if you need to use eager-loading methods such as has(), whereHas(), doesntHave(), whereDoesntHave()?
How do you pass an argument to the relationship? For example, I wanted to add other relationships to my User model.
public function children(Carbon $date=null)
{
$date = @$date ?: Carbon::now();
return self::whereHas('progenial_relation', function($q) {
$q->where('sponsor_id', $this->id);
}, $date); // not working
}
I tried with these syntax, but it doesn't work:
whereHas( 'relationship_name', $callback, $argument )
whereHas( 'relationship_name', $argument, $callback )
whereHas( 'relationship_name', [$argument], $callback )
whereHas( 'relationship_name', $callback, [$argument] )
Is it somehow possible? Are there any alternatives?
For completeness I'm going to add what happens if I use a normal closure:
public function children(Carbon $date=null)
{
$date = @$date ?: Carbon::now();
return self::whereHas('progenial_relation', function($q) use ($date) {
$q->at($date)->where('sponsor_id', $this->id);
});
}
This is the resulting SQL. As you can see the constraints are applied twice. Once by the query callback and once by the relationship. But since I cannot pass the correct argument to the relationship, it gets the default one. The 2 constraints collide and the query does not work.
"select * from `users`
where exists (
select *
from `user_relationships`
where `users`.`id` = `user_relationships`.`user_id`
and `user_relationships`.`superseded_at` > ?
and `user_relationships`.`created_at` <= ?
and `sponsor_id` = ?
and `user_relationships`.`superseded_at` > ?
and `user_relationships`.`created_at` <= ?
)
and `users`.`deleted_at` is null"
