基于foreignKey Laravel从表中检索数据

So I have 2 tables, articles and sub_categories. They are linked throug Eloquent: articles has many sub_categories's, and sub_categories belongsTo article. They are linked with foreign keys as such: in "article" categorie_id.

How do I retrieve the entire table data article where categorie is "DOG" for exemple Sorry for the abstraction, but this is the best way I can explain it? :D

article model

<?php
namespace App;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\SoftDeletes;

class Articles extends Model
{
    use SoftDeletes;

    public function user() {
        return $this->belongsTo('App\User') ;
    }

    public function sous_categories() {
        return $this->belongsTo('App\SouCategories') ;
    }
}

sub_categorie model

<?php
namespace App;

use Illuminate\Database\Eloquent\Model;

class SouCategories extends Model
{
    public function categories() {
        return $this->belongsTo('App\Categories') ;
    }

    public function articles() {
        return $this->hasMany('App\Articles','cat_id') ;
    }
}

in my controller i am trying to fetch data based on the foreign key on the sub_category and foreach sub category i am creating an a array like the mainslider contain articles that have a certain sub_category

public function index()
{
    $infos = Infos::all();
    $categories = Categories::all();
    $articles=Articles::all();   
    $mainslider=Soucategories::with('articles')->get();
    foreach($mainslider as $record){
        dd($record->articles);
    }
    die();
    return view('frontEnd.homepage',compact('infos','categories','articles','mainslider'));
}

According to the code you have posted it should be something like

Soucategories::where('title', 'DOG')->with('articles')->get();

it seems there will be only on Soucategory with name "DOG", so you can do something like

Soucategories::where('title', 'DOG')->first()->articles