Laravel数据库关系不会加载相关数据（编辑）

Question

I am trying to make a forum with sections and categories in laravel 5.7. All these sections has multiple categories.

When I build my relationship en try to get the data in the view, I get a error:

SQLSTATE[42S22]: Column not found: 1054 Unknown column 
'forum_categories.forum_section_id' in 'where clause' (SQL: select * from `forum_categories` where `forum_categories`.`forum_section_id` = 1 and `forum_categories`.`forum_section_id` is not null) 

This is my blade:

@foreach($sections as $section) 
                        <h1 data-toggle="collapse" data-target="#section{{$section->id}}">{{$section->name}}</h1>
                        <div class="collapse" id="section{{$section->id}}">
                            Dit is sectie
                            @foreach($section->ForumCategory as $forumCategory)
                                {{$forumCategory->id}}
                                @endforeach
                        </div>
 @endforeach

My Controller function index():

    $sections = ForumSection::all();
    return view('forum.index', compact(['sections'])); 

And this are My models: ForumCategory

namespace App;

use Illuminate\Database\Eloquent\Model;


class ForumCategory extends Model
{
  protected $fillable = [
     'name', 'active', 'position', 'section_id'
  ];
  public function ForumSection() {
     return $this->belongsTo(ForumSection::class, 'section_id');
  }
}

Model ForumSection :

 <?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class ForumSection extends Model
{
    protected $fillable = [
        'name','active', 'position'
    ];
    public function ForumCategory() {
        return $this->hasMany(ForumCategory::class, 'section_id');
    }
}

And Last: My 2 database tables:

ForumSectionsTable

public function up()
    {
            Schema::create('forum_sections', function (Blueprint $table) {
            $table->increments('id');
            $table->string('name');
            $table->boolean('active');
            $table->integer('position')->unique();
            $table->timestamps();
    });
}

ForumCategoriesTable

    public function up()
{
    Schema::create('forum_categories', function (Blueprint $table) {
        $table->increments('id');
        $table->string('name');
        $table->integer('active');
        $table->integer('section_id')->unsigned();
        $table->timestamps();
    });
    Schema::table('forum_categories', function (Blueprint $table)
    {
        $table->foreign('section_id')->references('id')->on('forum_sections');
    });
}

Can someone tell me what I am did wrong?

Answer 1

This one should be pretty clear... It's looking for

'forum_categories.forum_section_id'

as your linking id, but you're using

Schema::create('forum_categories', function (Blueprint $table) {
  ...
  $table->integer('section_id')->unsigned();
});

To solve this, you have a couple options: Override your migration and use forum_section_id instead of section_id , or add the ID to your relationship:

return $this->hasMany(ForumCategory::class, 'section_id');

You did that correctly for the belongsTo method, but seem to have missed it on the hasMany (inverse) method.

Next, use a loop to get a single id , as $seciton->ForumCategory is a Collection , and not a single Model:

@foreach($section->ForumCateogry AS $forumCateogry)
Dit is sectie {{ $forumCateogry->id }}
@endforeach

That brings up the note on naming conventions; method names are usually "camelCase", so forumCateogry() instead of ForumCateogry() , and pluralized for methods that return multiple, so forumCateogries() instead of forumCateogry()

Answer 2

解决的方法很简单...我将ForumCategory和ForumSection重命名为Category和Section，问题就消失了。