Eloquent Query for "BelongsToMany" Relationship - php

Question

When I want to query for all states a specific dispatch ticket in my database, I would do it like this:
public function test() {
$dispatches = Dispatch::where('dispatch_reference', '=', 'dis_548k14s4glnhv5')->get();
foreach($dispatches->states as $state) {
var_dump($state);
}
}
But this throws an error message, that states is not being recognized. The models I created are:
Dispatch
class Dispatch extends Model {
use EventGenerator;
protected $table = 'dispatches';
protected $fillable = ['dispatch_reference', 'incident_reference', 'state'];
public $timestamps = true;
// Since the FK exists in this table, the belongsTo() method is used to state that the dispatch model is related to an address.
// Dispatch __belongs_to__ Incident
public function incident() {
return $this->belongsTo('App\Classes\Incident');
}
// Dispatch __belongs_to_many__ State
public function states() {
return $this->belongsToMany('App\Classes\DispatchState')->withTimestamps();
}
public function attachDispatchState($id) {
$this->states()->attach($id);
$this->touch();
}
// set fields on the eloquent object and save to database
// raise event that the incident was created.
public function createDispatch($command) {
// Get BodyContent from POST Request
$this->dispatchReference = $command->dispatchReference;
$this->incidentReference = $command->incidentReference;
// Create new Dispatch
$dispatch = Dispatch::create(array(
'dispatch_reference' => $this->dispatchReference,
'incident_reference' => $this->incidentReference
));
$dispatchState = DispatchState::where('state', '=', 'processing')->first();
$dispatch->attachDispatchState($dispatchState->id);
return $this;
}
Dispatch State
class DispatchState extends Model {
use EventGenerator;
// Define Table Setup with fillabe fields
protected $table = 'dispatch_states';
// Fillable fields in database
protected $fillable = ['state'];
// include timestamps
public $timestamps = true;
// Status __belongs_to_many__ Dispatches
public function dispatches() {
return $this->belongsToMany('App\Classes\Dispatch');
}
}
I would expect to see all the different states attached to one dispatch as i am using a pivot table that works fine so far. I just cannot query the results. Do I have an error in my models?

Answer 1

When you're calling get() you're getting a collection of Dispatch object. If you expect to only get a single object (e.g. when dispatch reference is unique), call first() instead of get():
$dispatch = Dispatch::where('dispatch_reference', '=', 'dis_548k14s4glnhv5')->first();
If, however, dispatch reference is not unique, you'll need to first iterate through collection of dispatches and then through their related states:
$dispatches = Dispatch::where('dispatch_reference', '=', 'dis_548k14s4glnhv5')->get();
foreach($dispatches as $dispatch) {
foreach ($dispatch->states as $state) {
var_dump($state);
}
}