Laravel Eloquent Relation belongsTo update

Question

I am trying to update/delete/create in belongsTo relations.

Company has many sports sports is belonging to Company

Here is two models.

class CompanySports
{
    public function company()
    {
        return $this->belongsTo(Company::class, "company_id","id");
    }


    class Company
    public function sports()
    {
        return $this->hasMany(CompanySports::class,"company_id","id");
    }
}

at controller, when sports is added or modified or remove, what is the best practice to update?

i know that many to many, sync can be used. In this, what is the best solution? Should i compare everytime after loading all from database which is not good practice i believe.

Erich · Answer 1 · 2019-08-09T19:53:21.013

From your code, I would first recommend putting your models in separate files, and ensuring they are singular. If you use the artisan make:model command to generate the stubs, it should do this for you.

// app/CompanySport.php                // <-- NOTE singular

class CompanySport                     // <-- NOTE singular
{
    public function company()
    {
        return $this->belongsTo(Company::class, "company_id","id");
    }
}

// app/Company.php

class Company {
    public function sports()
    {
        return $this->hasMany(CompanySport::class,"company_id","id");  // singular
    }    
}

From there, I find it helpful to build helper methods in the various classes so that the grammar sounds natural and more importantly, belongs to the model. For example:

// app/Company.php

class Company
{
    ...

    public function addSport(CompanySport $sport)
    {
        $this->sports()->save($sport);
    }

    public function removeSport(CompanySport $sport)
    {
        $this->sports()->find($sport->id)->delete();
    }
}

These helper functions can then be easily called from anywhere, e.g. controller:

// CompanySportsController.php

public function store(Company $company, CompanySport $sport)
{
    $company->addSport($sport);

    return redirect('/company/' . $company->id);
}

If you are using these helpers, there is no comparing or sync to be done since you are only using a one to many relationship. Eloquent does everything for you.

Also, I've found this cheatsheet particularly helpful when building out the initial relationships and scaffolding of a new app.

score 0 · Answer 2 · answered Aug 09 '19 at 17:04

While adding new record of Company Model, you need not to do anything as there is no child for it yet.

While updating an instance of a Company model, again you need not to update anything on its children. As relationship are based on id(primary key) which I believe you don't change while updating.

And now for deleting there are some questions. Do you want to delete the children when the parent is deleting? If so, you can use ON DELETE CASCADE which you can set up in migration like

$table->foreign('company_id')->references('id')->on('companies')->onDelete('cascade');

in your spors table.

Well you can make your own function too like answered in here

Well if you don't want to delete the children, you can use softdelete on your Model. set up the relations then like

CompanySports

public function company()
{
    return $this->belongsTo(Company::class, "company_id","id")->withTrashed();
}

This way you can get the parent of a children without any error though the parent is deleted.

Laravel Eloquent Relation belongsTo update

2 Answers2