SQLSTATE [42S22]：未找到列：1054'where子句'中的未知列'categories.sub_category_id' - Laravel 5

Question

我有兩個表類別和子類別，我想用它們的連接子類別顯示類別。爲此，我創建了一個查詢。當我嘗試使用一對多關係從類別表中獲取類別名稱時顯示錯誤。

該表的結構爲
類別; ID，名稱
子類：身份證，CATEGORY_ID，子名

// Category.php model 
class Category extends Model 
{ 
    protected $primaryKey = 'id'; 
    protected $table = "categories"; 

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

// Subcategory.php model  
class SubCategory extends Model 
{ 
    protected $primaryKey = 'id'; 
    protected $table = "subcategories"; 

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

// Category Controller 
public function show() 
{  
    $categories= Category::all(); 
    $subcategories=Subcategory::all(); 
    return view('show',compact('categories','subcategories')); 
} 

// show.blade.php 
@foreach($subcategories as $subcategory) 
    {{ $subcategory->subname }} 
    {{ $subcategory->category_id }} 
    {{ $subcategory->category->name }} 
@endforeach 

此行給我的錯誤{{ $subcategory->category->name }}。

Answer 1

我需要改變的hasMany到屬於關聯

您是right因爲子類只有一個類別，你需要使用belongsTo關係

class SubCategory extends Model 
{ 
    protected $primaryKey = 'id'; 
    protected $table = "subcategories"; 

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