use relationship in model accessor in laravel - php

Suppose I have a Course model like this :
class Course extends Model
{
public $primaryKey = 'course_id';
protected $appends = ['teacher_name'];
public function getTeacherNameAttribute ()
{
$this->attributes['teacher_name'] = $this->teacher()->first()->full_name;
}
public function teacher ()
{
return $this->belongsTo('App\User', 'teacher', 'user_id');
}
}
And in the other hand there is a User model like this :
class User extends Authenticatable
{
public $primaryKey = 'user_id';
protected $appends = ['full_name'];
public function getFullNameAttribute ()
{
return $this->name . ' ' . $this->family;
}
public function course ()
{
return $this->hasMany('App\Course', 'teacher', 'user_id');
}
}
As you can see there is a hasMany relationship between those.
There is an full_name accessor in User model.
Now I want to add a teacher_name accessor to Course model that uses it's teacher relations and gets full_name of teacher and appends to Course always.
In fact I want whenever call a Course model, it's related teacher name included like other properties.
But every time , when call a Course model , I got this error :
exception 'ErrorException' with message 'Trying to get property of non-object' in D:\wamp\www\lms-api\app\Course.php:166
That refers to this line of Course model :
$this->attributes['teacher_name'] = $this->teacher()->first()->full_name;
I do not know how can I solve that and what is problem exactly.

Yikes some interesting answers here.
FYI to those coming after me- getFooAttribute() should return the data, and not modify the internal attributes array.
If you set a new value in the attributes array (that doesnt exist in this model's db schema) and then attempt to save the model, you'll hit a query exception.
It's worth reading up the laravel docs on attribute accessors/mutators for more info.
Furthermore, if you need to access a related object from within the model (like in an accessor) you ought to call $related = $this->getRelation('foo'); - note that if the relation isnt loaded (e.g., if you didnt fetch this object/collection with eager loaded relations) then $this->getRelation() could return null, but crucially if it is loaded, it won't run the same query(ies) to fetch the data again. So couple that with if (!$this->relationLoaded('foo')) { $this->loadRelation('foo'); }. You can then interact with the related object/collection as normal.

$this->attributes['teacher_name'] = $this->teacher()->first()->full_name;
Should be
$this->attributes['teacher_name'] = $this->teacher->full_name;
First thing is that you want to reference the relationship, so loose the brackets (), and because the relationship is belongsTo, you will have one user / teacher returned. So you don't need the first().
We haven't seen your fields but probably you will have to change:
return $this->belongsTo('App\User', 'teacher', 'user_id');
to
return $this->belongsTo('App\User', 'foreign_key', 'other_key');
where foreign_key and other_key are the primary keys that you need to make the join on.
Check this link from the documentation for reference:
https://laravel.com/docs/5.4/eloquent-relationships#one-to-many-inverse

the right way to do this is:
COURSE
public function setTeacherNameAttribute ()
{
$this->attributes['teacher_name'] = $this->teacher->full_name;
}

100% working for me.
I have one to one relationship between Order and Shipment. I have to add the accessor of shipments table column from orders table.
function getOrderNoAttribute()
{
$appendText = "OR100";
if($this->orderShipment()->first()) {
$appendText = $this->orderShipment()->first()->is_shipping === 1 ? "ORE100" : "OR100";
}
return $appendText . $this->attributes['id'];
}

This error is only object data to array use or array data to object data use.
example::
$var->feild insted of $var[feild]
$var[feild] insted of $var->feild

You should use return for accessors . something like this :
public function getTeacherNameAttribute ()
{
return $this->teacher()->first()->full_name ?? '';
}
maybe a course hasn't teacher.

Related

Laravel Eloquent getting data from relations

I have Task model. My Task model has some relationships and it currently looks like this:
class Task extends Model
{
use HasFactory;
public $timestamps = false;
public function city()
{
return $this->hasOne(City::class, 'id', 'city_id');
}
public function type()
{
return $this->hasOne(Type::class, 'id', 'type_id');
}
public function note()
{
return $this->hasOne(Note::class, 'id', 'note_id');
}
public function operator()
{
return $this->hasOne(User::class, 'id', 'operator_id');
}
}
Now, in my TasksController I need to get Tasks that match certain criteria, like this:
$tasks = Task::whereCityId($city->id)->whereTypeId($type->id)->get()->toArray();
The problem is that fields named city_id type_id note_id operator_id will get my integer values that they have.
Instead I would like to get certain value from a related Model.
For example:
operator_id should be replaced with username from User table that corresponds to the user id.
An obvious solution to this would be to simply use foreach loop, go through my results and get the data I need and simply create another array with the information replaced, but I am not sure if this is the best idea and perhaps there is something better.
You have to change in your code:
$this->hasOne(ClassName::class, 'id', 'foreign_key');
To
$this->belongsTo(ClassName::class, 'foreign_key', 'id');
because Task's id does not available as foreign key in these tables. These table's id present in task table as foreign key so you have to use belongsTo() relationship to tell script from where these id belongs.
Then access properties like this:
$tasks = Task::with("type", "city", "operator")
->whereCityId($city->id)->whereTypeId($type->id)->get();
foreach($tasks as $task){
echo $task->city->name;
}
first you should fix your relation:
public function city()
{
return $this->hasOne(City::class,'city_id','id');
}
and so one the same error, foreign key in argument order comes before the primary key.
after that you can use addSelect:
$tasks = Task::whereCityId($city->id)->whereTypeId($type->id)
->addSelect(['userName' => User::select('name')
->whereColumn('users.id', 'tasks.operator_id')
->limit(1)])->get()->toArray();
i think this will help better than what you ask.
$tasks = Task::whereCityId($city->id)
->whereTypeId($type->id)
->with('operator')
->get()->toArray();
with('operator') is ORM feature that make you collection to include its relation as collection property. In this case it will convert to array property.
you could access it from your foreach function as
#foreach($task as $key)
$key['operator']['username']
#endforeach
Have a nice day

How to get only one note from relation belongsToMany?

I just have a table that has relation belongsToMany, BUT it was a mistake by developer so I can not change this structure SO I need to get only first(). However, when I take only first it return empty array but I need in object
$animals = Cat::query()->with(['types' => function($query) {
$query->first(); //wrong
}])
So how I can get only first? Because I need to order by this field and I can't because it is array
you can do this in two ways:
1- using hasOne relation:
class Cat {
public function firstType() {
return $this->hasOne(Type::class, 'type_id', 'id')->latest();
}
}
2- using staudenmeir/eloquent-eager-limit
after installing it you can write:
class Cat extends Model
{
use \Staudenmeir\EloquentEagerLimit\HasEagerLimit;
public function firstType() {
return $this->hasMany(Type::class, 'type_id', 'id')->latest()->limit(1);
}
}
class Type extends Model
{
use \Staudenmeir\EloquentEagerLimit\HasEagerLimit;
// ......
}
the advantage of HasEagerLimit trait is that you can limit the result not only to one but any number you want ...
now you can write:
$animals = Cat::query()->with('firstType');
You can add a attribute getter and set up into appends attribute. follow bellow example:
class Cat {
protected $appends = ['type'];
public function getTypeAttribute() {
// return the first element from your array of the belongsToMany relationship if it exists
return isset($this->types[0])? $this->types[0] : null;
}
}
That's important to remember this method will bring just one type. If you want to get the same type everytime, you create a diferente table where the cat table has the type_id column.
obs: Sorry for my english, it's still in working progress.

Laravel Eloquent Model hasMany Error "Illuminate\Database\Eloquent\Relations\HasMany could not be converted to string"

I created an Eloquent Model :
class VehicleDetails extends Model
{
//
protected $table = 'v_vehicle_details';
protected $primaryKey = 'model_id';
public function tariffs()
{
return $this->hasMany('App\Tariffs', 'vehicle_model_id', 'model_id');
}
}
The table structure for the same is v_vehicle_details is
v_vehicle_details
The table structure for tariffs is
t_tariffs
The Model is being called in controller like :
public function booking_view(){
$vehicle_details = new VehicleDetails();
return $vehicle_details->find(5)->tariffs();
}
What I need is to get vehicle details with all tariffs, But when I try that it throws an error Illuminate\Database\Eloquent\Relations\HasMany could not be converted to string. Can somebody please help, I am new to laravel.
These are not actual tables, But views.
change to
return VehicleDetails::with('tariffs')->find(5);
This is because calling the method ->tarrifs() will return a relationship object in this case HasMany this means you still have to perform the query on this object to get the results.
If you use it as a property ->tarifs without () it will perform the query.
This is the same as tarifs()->get() just a shortcut.
Change your function to:
public function bookingView(){
$vehicle = VehicleDetails::with('tariffs')->find(5);
return view('your.view', compact('vehicle'));
}
The with() will eager load the tariffs relation.
You can acess your tariffs in your view like this:
{{$vehicle->tariffs->anyAttributeYouWantToAccess}}

Failure to extract data from a relationship with laravel

I am trying to make a one-to-many relationship, but I get the following error
Undefined property: stdClass::$client (View:
C:\wamp\www\intranet\resources\views\users\list.blade.php)
The problem is that I am working with an existing database that in the tables does not have id fields, and the foreign keys would also be the typical ones like client_id
My model Client.php
class Client extends Model
{
protected $connection = 'dpnmwin';
protected $table = 'nmundfunc';
public function employee(){
return $this->hasMany('App\Employee');
}
}
My model Employee.php
class Employee extends Model
{
protected $connection = 'dpnmwin';
protected $table = 'nmtrabajador';
public function client(){
return $this->belongsTo('App\Client', 'COD_UND');
}
}
In nmtrabajador COD_UND field would be the foreign key that relates to nmundfunc.
And I try to get the data out like this: {{$user->client->CEN_DESCRI}}.
but it does not throw me the error, how can I solve it?
My Controller where I send in sight
public function index(){
$users = DB::connection('dpnmwin')->table('nmtrabajador')->where('CONDICION', '=', 'A')->get();
return view('users.list',array(
'users' => $users
));
}
You have to call basis on relations.
This code will return you data.
If you have id then you can find by id like below
$employee=Employee::find(1);
Or if you want to fetch all data then you can call all method.
Employee::all();
And then you can just get it by relation as you define in models.
$client=$employee->client->CEN_DESCRI;
Retrieving data from the instance is based on the methods which we have use.
Here in this answer, you can get that
Property [title] does not exist on this collection instance
I hope it will work.
If table doesn't have 'id' as primary key you should specify what the primary key is inside your model:
protected $primaryKey = 'your_primary_key';
Relation looks good, after that you must make sure $user is a defined instance of Employee, because your error probably means that your instance wasn't even defined, so for example if you are using list.blade.php, you need to change the return of your controller and indicate that you want to pass data to your view, for example you could do it like this:
return view('users.list', compact('user'));
Where user is an instance of Employee saved on '$user'
Update
First you should check your user is retrieved properly, you can check it by placing a dd($user)
And when you return a view you can pass information to it, a cleaner way of doing what you are trying to do is what I wrote earlier so you would end up having something like this:
public function index()
{
$users = DB::table('nmtrabajador')
->where('CONDICION', '=', 'A')
->get();
// dd($user) for debugging you are retrieving the user properly
return view('users.list', compact($users));
}

Laravel 5 – get particular many to many relation based on model and related model ID

I've got Tag and Attendee Eloquent models, they are in many-to-many relation. Pivot table has also two more attributes – value_int and value_string. My Attendee model looks like this:
class Attendee extends Model
{
public $timestamps = false;
protected $fillable = [
'event_id'
];
public function tags() {
return $this->belongsToMany('App\Models\Tag', 'attendee_tag', 'attendee_id', 'tag_id')
->withPivot(['value_string', 'value_int']);
}
public function scoreTagValue($tag_id) {
return $this->tags->where('tag_id', '=', $tag_id)->first();
}
}
What I want is to obtain pivot values based on Attendee model and variable tag_id, so I've written scoreTagValue function, but it always returns null and I don't know why :( I'm calling it this way:
$attendee->scoreTagValue($tag_id). Thanks for your help :)
You need to access the relation, not the property:
public function scoreTagValue($tag_id) {
return $this->tags()->where('tag_id', '=', $tag_id)->first();
}
Also, according to the docs, withPivot() does not take an array, so:
->withPivot('value_string', 'value_int');

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