Laravel Eloquent“属于”关系书籍及其类别

Question

我正在尝试打印“书籍”表中所有书籍的名称及其关联的类别。但它不显示任何内容或错误消息。

型号::Book.php

class Book extends Eloquent{
    protected $table ='books';

    public function bookCat()
    {
        return $this->belongsTo('BookCategory');
    }
}

型号::BookCategory.php

class BookCategory extends Eloquent{
    protected $table ='book_categories';

}

控制器::route.php

Route::get('/', function()
{
    $books = Book::all();

    return View::make('books')
    ->with('books', $books);
});

查看::books.blade.php

@foreach ($books as $book)

<li>{{ $book->book_name }}</li>
- <small>{{ $book->bookCat }}</small>

@endforeach

表::书

(int)id, (string)book_name, (int)category_id

表::book_categories

（int）id，（字符串）类别

Answer 1

将关系添加到 BookCategory。

class BookCategory extends Eloquent{
    protected $table ='book_categories';

    public function books() {
        return $this->hasMany('Book');
    }
}

您的本地密钥也与模型名称不匹配，因此您需要在关系中指定：

class Book extends Eloquent{
    protected $table ='books';

    public function bookCat()
    {
        return $this->belongsTo('BookCategory', 'category_id');
    }
}

您可能还想在控制器中预先加载类别，因为您的查询是针对书籍的：

$books = Book::with('bookCat')->get();