Laravel eloquent for four tables - laravel

I'm new to Laravel. I am developing a project. and in this project I have 4 tables related to each other
-Users
-Orders
-OrderParcels
-Situations
When listing the parcels of an order, I want to get the information of that order only once, the user information of that order once again, and list the parcels as a table under it. so far everything ok. but I also want to display the status of the parcels listed in the table as names. I couldn't add the 4th table to the query. do you have a suggestion? I'm putting pictures that explain the structure below.
My current working code is
$orderParcels = Orders::whereId($id)
->with('parcels')
->with('users:id,name')
->first();
and my 'orders' model has method
public function parcels(){
return $this->hasMany(OrderParcels::class);
}
public function users(){
return $this->hasOne(User::class,'id','affixer_id');
}
Note[edit]: I already know how to connect like this
$orderParcels = DB::table('order_parcels as op')
->leftjoin('orders as o','op.orders_id','o.id')
->leftjoin('users as u','o.affixer_id','u.id')
->leftjoin('situations as s','op.status','s.id')
->select('op.*','o.*','u.name','s.situations_name')
->where('op.orders_id',$id)->get();
but this is not working for me, for each parcels record it returns me orders and user info. I want once orders info and once user info.

Laravel provides an elegant way to manage relations between models. In your situation, the first step is to create all relations described in your schema :
1. Model Order
class User extends Model {
public function parcels()
{
return $this->hasMany(OrderParcels::class);
}
public function users()
{
return $this->hasOne(User::class,'id','affixer_id');
}
}
2. Model Parcel
class Parcel extends Model {
public function situations()
{
return $this->hasOne(Situation::class, ...);
}
}
Then, you can retrieve all desired informations simply like this :
// Retrieve all users of an order
$users = $order->users; // You get a Collection of User instances
// Retrieve all parcels of an order
$parcels = $order->parcels; // You get a Collection of User instances
// Retrieve the situation for a parcel
$situations = $parcel->situations // You get Situation instance
How it works ?
When you add a relation on your model, you can retrieve the result of this relation by using the property with the same name of the method. Laravel will automatically provide you those properties ! (e.g: parcels() method in your Order Model will generate $order->parcels property.
To finish, in this situation where you have nested relations (as describe in your schema), you should use with() method of your model to eager load all the nested relation of order model like this :
$orders = Orders::with(['users', 'parcels', 'parcels.situations'])->find($id)
I encourage you to read those stubs of Laravel documentation :
Define model relations
Eager loading
Laravel Collection
Good luck !

Use join to make a perfect relations between tables.
$output = Orders::join('users', 'users.id', '=', 'orders.user_id')
->join('order_parcels', 'order_parcels.id', '=', 'orders.parcel_id')
->join('situations', 'situation.id', '=', 'order_parcels.situation_id')
->select([
'orders.id AS order_id',
'users.id AS user_id',
'order.parcels.id AS parcel_id',
'and so on'
])
->where('some row', '=', 'some row or variable')->get();

Related

Laravel: With and whereHas to filter second relation hasOne

i'm trying to filter the table using "with" and "whereHas" for the relation and have it follow a second second relation.
Is it possible to do it with "with" or would it only be possible with "Joins"?
Ticket >> StatusHistory (Last record) >> StatusName = 'new'
ticket
-id
-name
status_history
- ticket_id
- status_name_id
- timestamps
status_names
- id
- name (new, close, paused)
<?
class Ticket extends Model
{
public function latestStatus()
{
return $this->hasOne(StatusHistory::class, 'ticket_id', 'id')->latest();
}
class StatusHistory extends Model
{
public function statusName()
{
return $this->hasOne(StatusName::class, 'id', 'status_name_id');
}
This usually works well if there is only one Status history record, but if there are more, it returns values that should not be there.
example: ticket_id 1 has in history first status new and them status paused
With this sentence he returned the ticket to me even so he no longer has the last status in "new".
Ticket::with('latestStatus')
->whereHas('latestStatus.statusName', function($q){
$q->where('name', 'new');
})
According to the documentation (https://laravel.com/docs/8.x/eloquent-relationships#constraining-eager-loads) it is possible. It would look like this:
Ticket::with(['latestStatus' => function($q){
$q->where('name', 'new');
}])->get();
So that the subquery is linked to the relation you are trying to load
To access the first relationship you just use:
$ticket = Ticket::find($id);
$ticket->latestStatus
By having a "hasOne" relationship established, this will return the related record, which from what I see also has a hasOne relationship, so you can do the following:
$ticket->latestStatus->statusName
In this way, you are accessing the second relationship and working it as usual.
However, this is not the only way, as Laravel also offers access to chained relationships through the "has-one-through" method, which according to the documentation is defined as:
"...this relationship indicates that the declaring model can be matched with one instance of another model by proceeding through a third model."
class Ticket extends Model{
public function statusName()
{
return $this->hasOneThrough(StatusName::class, StatusHistory::class);
}
}
Take into account that for this you must follow the conventions established by Laravel. I leave here the related links, I am sure they will be very helpful. Greetings.
Relationships: one-to-one
Relationships: has-one-through

getting the latest item of the pivot relationship

I have a pivot relationship as below:
public function users()
{
return $this->belongsToMany(User::class,'pet_owners','pet_id','owner_id');
}
now in my controller i want to get the latest item of this pivot table which is sorted by created_at field . here is how i get it now :
$pets = Pet::with('users')->get();
return new PetResource($pets);
here I want to show all pets with the latest user entered for that pet in the pivot table
You can use this way,
$pets = Pet::whereHas('users', function($q){
$q->orderBy('id', 'DESC');
})->get();
return new PetResource($pets);
// return latest record of pivot table
Limiting eager loads is unfortunately not easily done with Eloquent. There are many issues related to this on the Github repo. You can read this thread for an overview.
One of Laravel's contributors released a package staudenmeir/eloquent-eager-limit to make it easier to limit eager loads. You can install it with:
composer require staudenmeir/eloquent-eager-limit:"^1.0"
You need to add the \Staudenmeir\EloquentEagerLimit\HasEagerLimit; trait to both your Pet and User models. Then you'll be able to use the limit method on a query inside a with method on your model:
$pets = Pet::with(['users' => function ($query) {
return $query->latest()->limit(1);
}])->get();

Complicated Eloquent relationship using `Model::query`

I have a complicated relationship I'm trying to establish between two models.
The goal is to use $supplier->supply_orders to access the orders where the user supplies an item.
This throws: LogicException: Relationship method must return an object of type Illuminate\Database\Eloquent\Relations\Relation.
With the code I've got I can use $supplier->supply_orders()->get(), however, when I try to use it as a relationship it throws. Since this is a relationship I should be able to wrap it in a relationship, but how would I go about doing that?
Supplier Model:
class Supplier extends Model {
public function supply_orders() {
return Order::query()
->select('order.*')
->join('item_order', 'order.id', '=', 'item_order.order_id')
->join('item', 'item_order.item_id', '=', 'item.id')
->where('item.supplier_id', '=', $this->id);
}
}
~~~ A whole lot of back info that I don't think you need but might ~~~
sql tables:
supplier
- id
items:
- id
- supplier_id
item_order:
- id
- order_id
- item_id
orders:
- id
The other Eloquent Models:
class Item extends Model {
public function orders() {
return $this->belongsToMany('Order');
}
}
class Order extends Model {}
Example of how this should work:
$supplier = factory(Supplier::class)->create();
$item = factory(Item::class)->create([
'supplier_id' => $supplier->id,
]);
$order = factory(Order::class)->create();
$order->items()->attach($item);
$orders = $supplier->supply_orders // Throws LogicException
This throws: LogicException: Relationship method must return an object of type Illuminate\Database\Eloquent\Relations\Relation
Sounds like a hasManyThrough with a many to many relationship. Laravel has no inbuilt support for this but you can always go ahead and write your own relationship like this: https://laravel.io/forum/03-04-2014-hasmanythrough-with-many-to-many
If you dont want relationships you can always do something like:
Order::whereHas('items.supplier', function($query) use($supplier) {
$query->where('id', $supplier->id);
});
For this to work, you need to have a relationship function items in your Order model and a relationship function supplier in your item model
I believe the reason it throws a relationship error is that you haven't created an Eloquent relation for
$supplier->supply_orders.
Instead, Laravel looks at your supply_orders() as a method in the class, and thus can't figure out which table to use as the pivot. To get the base relationship to work within Eloquent, you'd need to create a new pivot table for the relationship between suppliers and orders something like:
suppliers
-id
orders
-id
order_supplier
-id
-order_id
-supplier_id
From here, Laravel will accept a simple many to many relationship between the two (this would not cause a failure):
Supplier Class:
/**
* Get all orders associated with this supplier via order_supplier table
*
* #return \Illuminate\Database\Eloquent\Relations\BelongsToMany
*/
public function orders(){
return $this->belongsToMany("\App\Order");
}
Now that the relationship is solid both between the suppliers and orders, as well as the orders and items, you can eager load the relationship in all directions. Where it gets complicated for your particular need with the current DB setup is that you have a 3rd parameter from the items table that is not a direct pivot. Without having to re-structure the DB, I think the easiest would be to load your suppliers and the relationships like normal:
$suppliers = Supplier::with('orders', function($query) {
$query->with('items');
});
From here you've got all the relationships loaded and can draw down the ones with the right item->ids in a follow-up to the $suppliers collection. There are quite a few ways to skin the cat (even including all in one query) now that you have the Eloquent relationship... but I tend to keep it a little more simple by breaking it into a few readable bits.
Hope this helps.

Database relation with Laravel Eloquent ORM

I'm new to Laravel and I'm stuck. This is what I am struggling with:
$questions = Question::find($id)->quiz(); // this code retrieves data from
// the table using the primary key
// in the table. The is a parameter
// that is passed via get.
This is what I have right now:
$questions = Question::where('quiz_id', '=', $id)->quiz();
This is the error I get:
Call to undefined method Illuminate\Database\Query\Builder::quiz()
What I want to do:
I want to run a query to get data from my database table using the foreign key in the table not the primary key, I also want to be able to use relations with this as seen from what I tried to do above.
Edit: Added the Question Model
<?php
class Question extends Eloquent{
protected $table = 'quiz_questions';
public function quiz()
{
return $this->belongsTo('Quiz');
}
}
Calling the quiz() function from Question::find($id)->quiz() will return a Query Builder instance allowing you to query the parent of the Question, its not going to return any data at that point until you call ->get() or another method that actually executes the query.
If you're wanting to return all the questions belonging to a certain quiz then you can do it like this.
$questions = Question::where('quiz_id', $id)->get();
This will return an Eloquent\Collection of the results for all questions with a quiz_id that is equal to $id.
If you've setup the relations between the Quiz and Questions then you can also do this using the Laravel relations.
$quiz = Quiz::findOrFail($id);
foreach($quiz->questions as $question)
{
// Do stuff with $question
}
Laravel will automagically pull Questions from the database that belongTo the Quiz you've already got from the database, this is known as eager loading http://laravel.com/docs/4.2/eloquent#eager-loading
Wader is correct, just calling where() will not execute your query. You either call get() and get an iterable result or use first() if you only want one result.
$quiz = Question::where('quiz_id', '=', $id)->first()->quiz();

Laravel 3 Eloquent ORM usage

I have the following code which works but doesn't seem to follow the laravel eloquent way:
Article::left_join('images', 'articles.id', '=', 'images.article_id')
->join('article_category', 'articles.id', '=', 'article_category.article_id')
->where('article_category.category_id', '=', $category_id)
->get();
I have 4 tables; articles and categories which have a many to many relationship with each other, a pivot table article_category table which holds the article id and category id and an image table which has one to one relationship with an article.
I setup my models as:
class Category extends Eloquent {
public static function get_articles($category_id) {
return static::find($category_id)->has_many_and_belongs_to('Article');
}
class Article extends Eloquent {
public function categories() {
return $this->has_many_and_belongs_to('Category');
}
public function image() {
return $this->has_one('Image');
}
However I can't seem to get all three bits of info together. I can do:
Category::get_articles($current_category)->get();
To get all articles in a given category but I can't seem to get the image for the article, there seems to be nothing I can chain onto? Unless I'm doing it incorrectly? Is there a trick I'm missing?
I even tried the stripped down version from the docs:
foreach (Article::with('image')->get() as $article) {
echo $article->image->foo;
}
However I get an error: Trying to get property of non-object, even though var_dump shows $article->image is an object! Weird.
Thanks
If you have not setup a model for the image table, do that. The ORM needs the model there so it knows what 'Image' refers to.
Can you get the category information using the ::with method or is that troublesome too?

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