php - MySQL 多表关系

Question

我有下表:

 Makes:
 id - make_name

 Models:
 id - model_name - make_id

 Trims:
 id - trim_name - model_id

 Forsale_Cars:
 id - trim_id - year - price

我的问题是，如果用户选择(品牌 ID)，我如何返回该品牌下列出的并且也存在于 Forsale_Cars 表中的所有装饰？

Answer 1

在 Eloquent 中，这对你有用:

$make = Make::find($selectedId);
$trims = $make->trims()->has('forsales')->get();
// returns collection of Trim models that have related row in foresale_cars

// to also load the forsales models you can then do this (load on the collection):
$trims->load('forsales');
// or instead in one chain
$trims = $make->trims()->has('forsales')->with('forsales')->get();

您需要在 Make 模型上建立此关系:

public function trims()
{
  return $this->hasManyThrough('Trim', 'Model');
}

其他关系如您上一个问题 MySQL relation with multiple tables