无法从一对多关系访问 laravel 5.8 中的数据

Question

I new to laravel. I have been trying to set a 1 to many realtionship between post and category, I can access the category using the post_id but not the reverse. I get the following error,

"Trying to get property 'category' of non-object"

This is my web.php

<?php
use App\Post;

Route::get('/test',function()
{
    return App\Post::find(3)->category;

});

This is from post.php

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

This is from category.php

 public function posts()
    {
        return $this->hasMany('App\Post');
    }

This is Post.php

<?php

namespace App;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Softdeletes;

class Post extends Model
{

    protected $fillable =[
        'title', 'content', 'category_id', 'featured', 'slug'
    ];

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

    public function tag()
    {
        return $this-> belongsToMany('App\Tag');
    }

    use SoftDeletes;


    public function getFeaturedAttribute($featured)
    {
        return asset($featured);
    }
.......

This is Category.php

<?php

namespace App;


use Illuminate\Database\Eloquent\Model;

class Category extends Model
{

protected $fillable = ['name'];

    public function posts()
    {
        return $this->hasMany('App\Post');
    }
}

Answer 1

The find method finds a model that has a given primary key. In your web.php App\Category::find(7) returns a category instance of id 7. I'm guessing what you are trying to do is App\Post::find(7)->category in other word you are trying to retrieve the post of id 7 and get its category; If not you are probably trying to access the posts of one category of id 7 in which case you should code App\Category::find(7)->posts .

Answer 2

maybe you need App\Category::find(7)->posts because Category model really doesn't have category property

Answer 3

I don't know what the problem was I closed everything and restarted. Everything worked fine.