Laravel 4 如何查询有说服力的多对多关系,以查看模型实例是否在集合中?
我的雄辩模型描述如下:Laravel 4 如何查询有说服力的多对多关系,以查看模型实例是否在集合中?,laravel-4,eloquent,Laravel 4,Eloquent,我的雄辩模型描述如下: class Product extends Eloquent{ ... public function categories(){ return $this->belongsToMany('Category'); } ... } class Category extends Eloquent{ ... public function products(){ return $this->belongs
class Product extends Eloquent{
...
public function categories(){
return $this->belongsToMany('Category');
}
...
}
class Category extends Eloquent{
...
public function products(){
return $this->belongsToMany('Product');
}
...
}
如何为给定产品是否属于某个类别编写结构清晰的查询
额外的爱,如果它能成为一种上课的方法
我最近(也是非常混乱)的尝试是:
$categories = Category::all();
$product = Product::find($id);
$id = 3;
foreach($categories as $cat)
while($cat->products())
if($product->id === $cat->products()->id)
true
endif
endwhile
endforeach
检查关系是否存在的最简单方法是:
$product = Product::whereHas('categories', function ($q) use ($categoryId) {
$q->where('categories.id', $categoryId);
})->findOrFail($productId);
这将返回产品实例,如果找不到,则抛出ModelNotFoundException
(表示给定id没有产品,或者产品与给定类别没有关系)
您还可以查看此项以了解更多线索:
您还可以在收藏中使用
包含:
$categories = Category::with('products)->get();
$product = Product::find($id);
foreach ($categories as $category)
{
if ($category->products->contains($product)
{
// do something
}
}
// note:
$category->products; // Eloquent Collection object
$category->products(); // BelongsToMany relation object
我用德佐的第二个建议来解决我的困境。见我的要点
$categories = Category::with('products)->get();
$product = Product::find($id);
foreach ($categories as $category)
{
if ($category->products->contains($product)
{
// do something
}
}
// note:
$category->products; // Eloquent Collection object
$category->products(); // BelongsToMany relation object