Laravel Eloquent associated function name

Question

I have two tables, namely "posts" and "categories". The relationship between "posts" and "categories" is many-to-one. Therefore, the code in the "Post" class model is as follows:

<?php

namespace AppModels;

use IlluminateDatabaseEloquentFactoriesHasFactory;
use IlluminateDatabaseEloquentModel;

class Post extends Model
{
    use HasFactory;

    protected $guarded = ['id'];

    public function category()
    {
        return $this->belongsTo(Category::class);
    }
}

Using this code, the application runs successfully.

The problem is when I try to change the category function name to "categories" and I try to access the post's category name like this:

Post::first()->categories->name, laravel give an error like this Attempt to read property "name" on null in D:BelajarProgramCODINGANLaravelapplicationcoba-laraveleval() 'd code.

(edited

When the Eloquent function name is "category", "Post::first()->category" returns the category of the post. However, when I try to change the function name to "categories" and access it using "Post::first()->categories", it returns null.

)

I tried changing the name of the Eloquent associated function in the category class model to a random name, but I can still access it and Laravel reports no errors. The code of the category class model is as follows:

<?php

namespace AppModels;

use IlluminateDatabaseEloquentFactoriesHasFactory;
use IlluminateDatabaseEloquentModel;

class Category extends Model
{
    use HasFactory;
    protected $guarded = ['id'];

    public function posts(){
        return $this->hasMany(Post::class);
    }
}

Can anyone help me? Why can I change the Eloquent function name in the category class model but not in the posts class model?

Answer 1

Doing the following should solve the problem:

public function categories()
{
    return $this->belongsTo(Category::class, 'category_id', 'id');
}