Laravel version:7.0
reviews table (Model - Review) has id, product_type, product_id, rating columns.
product_type can be service, plugin, module and each value has own model App\Service, App\Plugin, App\Module. I could put model names directly in product_type but I prefer to use those values.
Here is Review model relationship.
public function plugin()
{
return $this->belongsTo(Plugin::class, "product_id")->withDefault();
}
public function module()
{
return $this->belongsTo(Module::class, "product_id")->withDefault();
}
public function service()
{
return $this->belongsTo(Service::class, "product_id")->withDefault();
}
public function getItem()
{
if($this->product_type=='module')
{
return $this->module;
}elseif($this->product_type=='service')
{
return $this->service;
}else {
return $this->plugin;
}
}
Now I want to get them with eager loading in Review Model as following:
$reviews = Review::with("getItem")->get();
Without Eager loading, I could use $review->getItem()->name // this returns name of product.
How can I get them with eager loading?
You could have implemented this easily as a polymorphic relationship. In your Reviews Model, you could do this:
Model Structure
App\Review.php
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
class Review extends Model
{
public function reviewable()
{
return $this->morphTo();
}
}
Then add reviews() method to your App\Service, App\Plugin and App\Module models
public function reviews()
{
return $this->morphMany('App\Review', 'reviewable');
}
Table Structure
You reviews table could look like this:
reviews
id - integer
body - text
reviewable_id - integer
reviewable_type - string
Note the reviewable_id and reviewable_type fields. The reviewable_id stores the id of the item reviewed and the reviewable_type stores the model related to the item.
Retrieving The Relationship
You may access the relationships via your models. For example, to access all of the reviews for a service, we can use the reviews dynamic property:
$service = App\Service::find(1);
foreach ($service->reviews as $review) {
//
}
You may also retrieve the owner of a polymorphic relation from the polymorphic model by accessing the name of the method that performs the call to morphTo. In your case, that is the reviewable method on the Review model. So, we will access that method as a dynamic property:
$review = App\Review::find(1);
$reviewable = $review->reviewable;
The reviewable will return the model on the Review model either Service, Plugin or Module
Related
I have a model called CallbackRequest the model has a relationship with Loan model and that is the only relationship for CallbackRequest model.
CallbackModel:
public function loan() {
return $this->belongsTo(Loan::class);
}
Now Loan model itself has a relationship with a third model called Applicant.
Loan Model:
public function applicant() {
return $this->belongsTo(Applicant::class);
}
My point:
When I load CallbackRequest I eagerload loan model with it, all fine! But now I am wondering if there is a way to eagerload applicant model when I do:
Right now I access it like:
$modelResults = PublicCallback::with('loan')->get();
I get all callbacks with loan eagerloaded, but my point is I want when I eagerload loans in this case I want applicant to be loaded also !
Is there any way how to do this, is it possible ?
You can do this with:
$modelResults = PublicCallback::with(['loan', 'loan.applicant'])->get();
Ref: https://laravel.com/docs/5.5/eloquent-relationships#eager-loading
Just for posterity, there's also another way of loading nested relationships that can be done against a returned model, provided you have set up the relationships correctly:
Posts model:
public function comments() {
return $this->hasMany('App\Comment', 'quote_id', 'id');
}
Comments model:
public function user() {
return $this->belongsTo('App\User');
}
Then you can actually infer the user via relationship to a comment by drawing the post but loading an array of relations, eg:
$post = \App\Post::find($post_id);
return $post->load(['comments','comments.user']);
I'm trying to understand polymorphic relationship in Laravel. I know how it works in principle, but the choice of wording in Laravel is not intuitive in this part. Given the exanple,
namespace App;
use Illuminate\Database\Eloquent\Model;
class Like extends Model
{
/**
* Get all of the owning likeable models.
*/
public function likeable()
{
return $this->morphTo();
}
}
class Post extends Model
{
/**
* Get all of the product's likes.
*/
public function likes()
{
return $this->morphMany('App\Like', 'likeable');
}
}
class Comment extends Model
{
/**
* Get all of the comment's likes.
*/
public function likes()
{
return $this->morphMany('App\Like', 'likeable');
}
}
How do yo put in plain English sentence morphTo for instance? It is "belongsto"? and morphmany, hasMany? going further,
$post = App\Post::find(1);
foreach ($post->likes as $like) {
//
}
$likeable = $like->likeable;
morphToMany and morphByMany
How do you describe in plain english?
A polymorphic relationship means an object can have a relationship to more than one type of object. This is determined by two fields in the database rather the typical one foreign key field you would normally see.
Using the code you included in your question any type of object extending the Model class can have a relationship with a Like object. So you could have Comments and Posts that can have Likes associated to them. In your likes table you may have rows where 'likable_type' = 'post' and 'likable_id' = 1 or 'likable_type' = 'comment' and 'likable_id' = 4 for example.
I have a Detail (represents order details) model that I'd like to morph to either a sales order detail or a purchase order detail. So I create a table that has a 'type' column, which would have a value of 'sale' or 'purchase'.
My question is, is there a way in Laravel that I could morph the Detail model to Sale and Purchase, so that, for example, if I call App\Sale::all() it would fetch App\Detail::all()->where('type','sale') ?
Set the database tables:
You can set up your database tables in this structure :
purchases
id - integer
price - string
sales
id - integer
price - integer
details
id - integer
description - string
detailable_id - integer
detailable_type - string
Set your models:
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
class Detail extends Model
{
// Get all of the owning detailable models.
public function detailable()
{
return $this->morphTo();
}
}
class Sale extends Model
{
// Get all of the sales member's order details.
public function details()
{
return $this->morphMany('App\Detail', 'detailable');
}
}
class Purchase extends Model
{
// Get all of the purchase's order details.
public function details()
{
return $this->morphMany('App\Detail', 'detailable');
}
}
Retrieve data :
And then you can retrieve your sales like this :
$sales = App\Sale::find(1);
foreach ($sales->details as $order_detail) {
//
}
Same thing with purchases :
$purchases = App\Purchase::find(1);
foreach ($purchases->details as $order_detail) {
//
}
More about polymorphic relations : http://laravel.com/docs/5.1/eloquent-relationships#polymorphic-relations
Although I haven't found an "official" way to morph a single class to another. I developed the following way that could be a solution.
First, define two models Sale and Purchase that extends Detail, and use the trait that will define later.
class Sale extends Detail {
use SaleTrait;
}
Then, use GlobalScope to add constraints to query builder. Here are the steps:
Define a trait for Sale and Purchase model,
trait SaleTrait {
public static function bootSaleTrait()
{
static::addGlobalScope(new ActiveEventsScope);
}
}
Then define the scope. NOTE: here instead of implementing ScopeInterface, I extends Sofa\GlobalScope which handles remove() method for me, so I only need to define apply() in the scope.
class SaleScope extends GlobalScope
{
public function apply(Builder $builder, Model $model)
{
$builder->where('type', 'sale');
}
}
Now I could use App\Sale::all() and App\Purchase::all() to only retrieve what I want.
I'm using Laravel as a REST API for a SPA. I have a relationship where families have multiple contributions. The contributions table has a foreign key reference to family's id. I can call on the contributions route with the hasMany/belongsTo set up, and every contribution gets the entire family model it belongs to. But I don't need all that data, I just need a single field from the family table (not the id, but a different field) with each contribution.
Here are my models and resource controller:
class Family extends Eloquent {
protected $table = 'families';
// relationships
public function contributions() {
return $this->hasMany('Contribution');
}
}
class Contribution extends Eloquent {
protected $table = 'contributions';
// relationships
public function family() {
return $this->belongsTo('Family');
}
public function other_field() {
return $this->belongsTo('Family')->select('other_field');
}
}
class ContributionController extends BaseController {
public function index()
{
// works - but returns the entire family with every contribution
$contributions = Contribution::with('family')->get();
// returns other_field == null with every contribution
$contributions = Contribution::with('other_field')->get();
return Response::json($contributions->toArray(),
200);
}
Where am I going wrong with selecting this single field from the belongsTo relationship?
You can use query constraints on the relationship if you use eager loading.
Family::with(['contributions', function($query)
{
$query->select('column');
}])->get();
Using Laravel, I'm having some trouble accessing my other tables, which are all many to many.
So basically, I start out with the user id and want to list the customers that user has.
public function customers()
{
return $this->belongsToMany('Customer', 'user_to_customer');
}
This works, assume my user id is 1:
User::find(1)->customers;
However now I want to say, for each of these customers, list their products. However this needs to be within the same result.
I guess I would need something within the Customer model, such as:
public function products()
{
return $this->belongsToMany('Product', 'user_to_customer');
}
I can't seem to work out how to access this within the same query? Something like:
User::find(1)->customers->products;
Not sure.. any suggestions?
You can look into eager loading to accomplish this behavior. Given the following model relationships:
class User extends Eloquent {
public function customers()
{
return $this->has_many( 'Customer' );
}
}
class Customer extends Eloquent {
public function products()
{
return $this->has_many( 'Product' );
}
}
class Product extends Eloquent {}
The following query will return all products belonging to customers belonging to a specific (in this case, first) user:
User::with(array('customers', 'customers.products'))->first();