Laravel 5 cannot update relationship - php

Question

I've been trying for countless hours now, but still having issues updating a models relationship, the closest I've got to is a 'Method fill does not exist.' error.
Listing model:
class Listing extends Model
{
protected $fillable = [
'uid', 'start_date',...........
];
public function locations()
{
return $this->hasMany('App\ListingLocation');
}
}
Location (relationship to listing - hasMany):
class ListingLocation extends Model
{
protected $fillable = [
'listing_id', 'location',
];
public function listing()
{
return $this->belongsTo('App\Listing');
}
}
This returns my model and relationship, which I can view with dd($listing)
$listing = Listing::with('locations')->findOrFail($id);
This will update my listing model, which I can see the changes after calling dd($listing) again
$listing->fill($array);
However when I attempt to fill the relationship as per below, I get 'Method fill does not exist.'
$listing->locations->fill($array['locations']);
How can I update the relationship successfully before calling $listing->push();?

Answer 1

Change your location to a single record, not a collection
For example:
$listings->locations->first()->fill($array['locations']);
to fill every record use foreach
#foreach($listings->locations as $location)
$location->fill(do_something);
#endforeach

Answer 2

I ended up creating a new class to extend hasMany which allowed me to use sync as per alexweissman at https://laracasts.com/discuss/channels/general-discussion/syncing-one-to-many-relationships.
Extract from forum:
use Illuminate\Database\Eloquent\Relations\HasMany;
/**
* #link https://github.com/laravel/framework/blob/5.4/src/Illuminate/Database/Eloquent/Relations/HasMany.php
*/
class HasManySyncable extends HasMany
{
public function sync($data, $deleting = true)
{
$changes = [
'created' => [], 'deleted' => [], 'updated' => [],
];
$relatedKeyName = $this->related->getKeyName();
// First we need to attach any of the associated models that are not currently
// in the child entity table. We'll spin through the given IDs, checking to see
// if they exist in the array of current ones, and if not we will insert.
$current = $this->newQuery()->pluck(
$relatedKeyName
)->all();
// Separate the submitted data into "update" and "new"
$updateRows = [];
$newRows = [];
foreach ($data as $row) {
// We determine "updateable" rows as those whose $relatedKeyName (usually 'id') is set, not empty, and
// match a related row in the database.
if (isset($row[$relatedKeyName]) && !empty($row[$relatedKeyName]) && in_array($row[$relatedKeyName], $current)) {
$id = $row[$relatedKeyName];
$updateRows[$id] = $row;
} else {
$newRows[] = $row;
}
}
// Next, we'll determine the rows in the database that aren't in the "update" list.
// These rows will be scheduled for deletion. Again, we determine based on the relatedKeyName (typically 'id').
$updateIds = array_keys($updateRows);
$deleteIds = [];
foreach ($current as $currentId) {
if (!in_array($currentId, $updateIds)) {
$deleteIds[] = $currentId;
}
}
// Delete any non-matching rows
if ($deleting && count($deleteIds) > 0) {
$this->getRelated()->destroy($deleteIds);
$changes['deleted'] = $this->castKeys($deleteIds);
}
// Update the updatable rows
foreach ($updateRows as $id => $row) {
$this->getRelated()->where($relatedKeyName, $id)
->update($row);
}
$changes['updated'] = $this->castKeys($updateIds);
// Insert the new rows
$newIds = [];
foreach ($newRows as $row) {
$newModel = $this->create($row);
$newIds[] = $newModel->$relatedKeyName;
}
$changes['created'][] = $this->castKeys($newIds);
return $changes;
}
/**
* Cast the given keys to integers if they are numeric and string otherwise.
*
* #param array $keys
* #return array
*/
protected function castKeys(array $keys)
{
return (array) array_map(function ($v) {
return $this->castKey($v);
}, $keys);
}
/**
* Cast the given key to an integer if it is numeric.
*
* #param mixed $key
* #return mixed
*/
protected function castKey($key)
{
return is_numeric($key) ? (int) $key : (string) $key;
}
}
You can then override Eloquent's hasMany method in your model class:
/**
* Overrides the default Eloquent hasMany relationship to return a HasManySyncable.
*
* {#inheritDoc}
*/
public function hasMany($related, $foreignKey = null, $localKey = null)
{
$instance = $this->newRelatedInstance($related);
$foreignKey = $foreignKey ?: $this->getForeignKey();
$localKey = $localKey ?: $this->getKeyName();
return new HasManySyncable(
$instance->newQuery(), $this, $instance->getTable().'.'.$foreignKey, $localKey
);
}
/**
* Get all of a user's phone numbers.
*/
public function phones()
{
return $this->hasMany('App\Phone');
}
A sync method will now be available to any hasMany relationships you have on this model:
$user->phones()->sync([
[
'id' => 21,
'label' => "primary",
'number' => "5555551212"
],
[
'id' => null,
'label' => "mobile",
'number' => "1112223333"
]
]);