The User model has a one to one relationship with the PhoneNumber class:
public function phoneNumber() {
return $this->hasOne(PhoneNumber::class);
}
Yet, if the PhoneNumber table has multiple rows with the same user_id (for example 1), multiple models are returned from the Eloquent statement.
$multiplePhoneNumbers = User::find(1)->phoneNumber()->get();
This begs the question, what is the purpose of the hasOne() vs. hasMany() relationship?
phoneNumber() returns the query builder instance, to where you can append more methods like where() or orderBy() for example. Calling get() from that just executes the query without the added hasOne logic.
Behind the hood, the relationship will return the first result if you use it correctly.
User::find(1)->phoneNumber will return either a phone number or null.
Related
I have this database structure. 2 tables: shipment_out, stock_move.
shipment_out has the typical primary key integer id field.
stock_move has a field named shipment which is string type. This field can have these values:
"stock_shipment_out,1512",
"stock_shipment_in,65400",
"sale.line,358",
(...)
The thing is the table stock_move is related to a multiple tables based on the same field, so it has this text before.
In this case I want to define the relationship: shipment_out hasMany stock_move.
So I need to join by stock_move.shipment has this value: 'stock_shipment_out,{id}'.
So how can I define this relationship? Would be something like:
public function stockMoves()
{
return $this->hasMany(StockMove::class, 'shipment', 'stock.shipment.out,id');
}
I can achieve this relationship with query builder:
$shipments = ShipmentOut
::join('public.stock_move', DB::raw('CONCAT(\'stock.shipment.out,\',public.stock_shipment_out.id)'), '=', 'stock_move.shipment')
->where('stock_shipment_out.id', '=', $shipmentOut);
But I need on a relationship too...
To solve this problem I had to define a custom attribute, and then I can define the relationship with this field.
public function getStockMoveShipmentAttribute()
{
return "stock.shipment.out,{$this->id}";
}
public function stockMoves()
{
return $this->hasMany(StockMove::class, 'shipment', 'stock_move_shipment')
}
Now I can use this relationship, but it's only one-direction...
If I want to define the same relationship as the inverse it doesn't work.
I opened another question explaining it: Laravel relationship based on custom attribute not working both directions
I need to get counts of all the records based on belongsToMany relationship. normally I can use groupBy() in a function inside the model. but if I use count() or withCount() inside a model function, i get the error as followed:
function code:
public function TaskCount(){
return $this->belongsToMany(User::class)->count();
}
Error message:
Symfony\Component\Debug\Exception\FatalThrowableError: Call to a member function addEagerConstraints() on int in file /Users/dragonar/Dev/iyw/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Builder.php on line 560
If I do the following...
public function TaskCount(){
return $this->belongsToMany(User::class)->Count();
}
//expected record is 4(int)
//output is 4(array) user records.
...it gives me data but like 4 records of the user instead of a number 4. The user data is useless. The only thing needed is totalCount for those records.
Relationship methods have to return Relation type objects. You are returning the result of a query, count() returns a number not the Relation object / Builder. Remove the count from that statement you are returning. Renamed the relationship tasks here.
public function tasks()
{
return $this->belongsToMany(User::class);
// this returns a Relation type object a BelongsToMany object
}
Where you need to use that relationship you can then use count:
$something->tasks()->count();
Or you can load the count of the relationship using loadCount:
$something->loadCount('tasks');
$something->tasks_count;
Or via eager loading for a collection:
$results = Something::withCount('tasks')->get();
foreach ($results as $model) {
echo $model->tasks_count;
}
If you really wanted to you could create an accessor to get the count as well, you just may want to avoid the N+1 issue by preloading the relationship and using the dynamic property to access it in the accessor.
These relation objects are Builders. When you called groupBy on it previously that is returning the Builder, it isn't executing the query. You can add where conditions and order by statements because they are just building the query, not executing it, they return the builder you are calling the method on.
Laravel 6.x Docs - Eloquent - Relationships - Counting Related Models withCount loadCount
Why not use: Task::all()->count(); ?
you can use the withCount method while calling relation like this
User::withCount('images')->get();
You can add get the data and just count it.
public function TaskCount(){
return $this->belongsToMany(User::class)->get()->count();
}
You can call it like
$taskCount = $task->TaskCount();
Assume I have a User model, and also I have Couple model which forms of 2 users, father_id and mother_id which are essentially user_ids
On User model, I have
public function kids() {
return $this->hasMany('App\Kid', 'father_id');
}
However, I want to check if user_id is either father_id or mother_id, return the related Kid model.
Is there a way to achieve it with a single relationship? What is the proper way of handling this scenario, so I can use $user->kids that would check for both cases?
There is a way, but you wouldn't typically use it to "check" if there are related models.
If you have a field that determines if the model is representing a father or mother, such as is_father, you could do:
public function kids()
{
return ($this->is_father)
? $this->hasMany(Kid::class, 'father_id')
: $this->hasMany(Kid::class, 'mother_id');
}
Essentially, the relationship method MUST return a relationship instance. But you can do logic before you return this.
NOTE: The relationship is cached, so even if the is_father value changes in the same thread run, it will utilize the same relationship that it did before. This can cause unwanted bugs.
I'm using laravel and eloquent.
Actually I have problems filtering results from a table based on conditions on another table's attributes.
I have 3 tables:
venue
city
here are the relationships:
a city has many locations and a location belongs to a city.
a location belongs to a venue and a venue has one location.
I have a city_id attribute on locations table, which you may figured out from relationships.
The question is simple:
how can I get those venues which belong to a specific city?
the eloquent query I expect looks like this:
$venues=Venue::with('location')->where('location.city_id',$city->getKey());
Of course that's not gonna work, but seems like this is common task and there would be an eloquent command for it.
Thanks!
A couple of options:
$venues = Venue::whereIn('location_id', Location::whereCityId($city->id)->get->lists('id'))
->get();
Or possibly using whereHas:
$venues = Venue::whereHas('location', function($query) use ($city) {
$query->whereCityId($city->id);
})->get();
It is important to remember that each eloquent query returns a collection, and hence you can use "collection methods" on the result. So as said in other answers, you need a Eager Loading which you ask for the attribute you want to sort on from another table based on your relationship and then on the result, which is a collection, you either use "sortBy" or "sortByDesc" methods.
You can look at an example below:
class Post extends Model {
// imagine timpestamp table: id, publish, delete,
// timestampable_id, timestampble_type
public function timestamp()
{
return $this->morphOne(Timestamp::class, 'timestampable');
}
}
and then in the view side of the stuff:
$posts = App\Post::with('timestamp')->get(); // we make Eager Loading
$posts = $posts->sortByDesc('timestamp.publish');
return view('blog.index', compact('posts'));
I have a class Report which has a belongsToMany relation to Metric. Report also additionally has a belongsTo relation to Metric.
Normally, the model returned by the belongsTo relation is the same as one of the models in the belongsToMany relation. When this is true I'd like it to be the case that each of the two relations actually looks at the same object instance (this also saves an extra trip to the db).
So, in basic terms - is there a way to get one relation to check another first, to see if a model has already been loaded, and if so, point to that object rather than creating a new one.
I tried putting some code in the belongsTo relation method for Metric but I can't get round the fact it needs to return an instance of belongsTo, which needs various things passed as constructor arguments (ie. a query object), which aren't relevant in that case that the model has already been loaded in the belongsToMany relation.
I thought of ditching the belongsTo relation and adding data horizontally in the pivot table for the belongsToMany relation, but it isn't a many-to-many relation required so that seems a bit wrong.
Thanks!
Geoff
The idea here is to write a function which would check if a relationship is loaded and return that relationship, otherwise it will return the belongsToMany. This would go in your Report class. This is also for Laravel 5. If you have 4, just remove the namespaces from the model names.
public function metric()
{
return $this->belongsTo('App\Metric');
}
public function metrics()
{
return $this->belongsToMany('App\Metric');
}
public function getMetric()
{
if(array_key_exists('metric', $this->getRelations())) {
return $this->metric;
}
return $this->metrics()->first();
}
If you do decide to just go with a belongsToMany only, I'd suggest putting a unique key on your pivot table for both ID's to keep from getting any duplicates in the pivot table.