Laravel - 渴望加载多态关系的相关模型 [英] Laravel - Eager Loading Polymorphic Relation's Related Models
问题描述
我可以加载多种关系/模型，没有任何n + 1个问题。但是，如果我尝试访问与多态模型相关的模型，则出现n + 1问题，我似乎找不到修复。这是在本地查看的确切设置：
1）数据库表名/数据
历史
公司
产品
< br>
服务
2）模型 / p>
//历史
类历史延伸Eloquent {
protected $ table ='history';
public function historable（）{
return $ this-> morphTo（）;
}
}
//公司
class公司扩展Eloquent {
protected $ table ='companies'
//每个公司都有很多产品
public function products（）{
return $ this-> hasMany（'Product'）;
}
//每个公司都有很多服务
public function services（）{
return $ this-> hasMany（'Service'）;
}
}
//产品
class产品扩展Eloquent {
//每个产品属于一个公司
public function company（ ）{
return $ this-> belongsTo（'Company'）;
}
public function history（）{
return $ this-> morphMany（'History'，'historable'）;
}
}
//服务
类服务扩展Eloquent {
//每个服务属于一个公司
public function company ）{
return $ this-> belongsTo（'Company'）;
}
public function history（）{
return $ this-> morphMany（'History'，'historable'）;
}
}
3）路由 / p>
Route :: get（'/ history'，function（）{
$ historyories = historyable'） - > get（）;
return View :: make（'historyTemplate'，compact（'history））;
}）;
4）具有n + 1日志记录的模板是由$ history-> historable->公司 - >名称，评论，n + 1离开..但我们需要这个遥远的相关公司名称：
@foreach（$ history作为$ history）
< p>
< u> {{$ history-> historable-> company-> name}}< / u>
{{$ history-> historable-> name}}：{{$ history-> historable-> status}}
< / p>
@endforeach
{{dd（DB :: getQueryLog（））;我需要能够快速加载公司名称（在单个查询中），因为它是多元关系模型 Product 和 Service 的相关模型。
我一直在努力工作几天，但找不到解决方案。
历史:: with（'historable.company'） - > get（）只是忽略公司 historable.company 。
这个问题的有效解决方案是什么？解决方案 解决方案： p>
如果你添加，可以：
protected $ with = ['company'];
两个服务和产品型号。这样，每次服务或产品公司 / code>被加载，包括通过与 History 的多态关系加载时。
说明：
这将导致另外2个查询，一个用于服务，另一个用于 Product ，即每个 historable_type 。所以你的查询总数 - 不管结果的数量 n -goes from m + 1 （without eager-将远程公司关系）加载到（m * 2）+1 ，其中 m 是由多态关系链接的模型数。
可选：
这种方法的缺点是，您将永远在服务公司关系c>和产品型号。这可能是或可能不是一个问题，具体取决于您的数据的性质。如果这是一个问题，您可以使用此技巧在调用多态关系时自动加载公司 。
将此添加到您的历史模型中：
{
if（is_null（$ value））返回值（$ value）
return（$ value.'WithCompany'）;
}
现在，加载 historable 多态关系，Eloquent将寻找 ServiceWithCompany 和 ProductWithCompany ，而不是服务或产品。然后，创建这些类，并在其中设置 ：
ProductWithCompany.php
class ProductWithCompany extends Product {
protected $ table ='products';
protected $ with = ['company'];
}
ServiceWithCompany.php
class ServiceWithCompany extends Service {
protected $ table ='services';
protected $ with = ['company'];
}
...最后，您可以删除 protected $ with = ['company']; 从基础服务和产品类。
有点黑客，但它应该有效。
I can eager load polymorphic relations/models without any n+1 issues. However, if I try to access a model related to the polymorphic model, the n+1 problem appears and I can't seem to find a fix. Here is the exact setup to see it locally:
1) DB table name/data
history
companies
products
services
2) Models
// History
class History extends Eloquent {
protected $table = 'history';
public function historable(){
return $this->morphTo();
}
}
// Company
class Company extends Eloquent {
protected $table = 'companies';
// each company has many products
public function products() {
return $this->hasMany('Product');
}
// each company has many services
public function services() {
return $this->hasMany('Service');
}
}
// Product
class Product extends Eloquent {
// each product belongs to a company
public function company() {
return $this->belongsTo('Company');
}
public function history() {
return $this->morphMany('History', 'historable');
}
}
// Service
class Service extends Eloquent {
// each service belongs to a company
public function company() {
return $this->belongsTo('Company');
}
public function history() {
return $this->morphMany('History', 'historable');
}
}
3) Routing
Route::get('/history', function(){
$histories = History::with('historable')->get();
return View::make('historyTemplate', compact('histories'));
});
4) Template with n+1 logged only becacuse of $history->historable->company->name, comment it out, n+1 goes away.. but we need that distant related company name:
@foreach($histories as $history)
<p>
<u>{{ $history->historable->company->name }}</u>
{{ $history->historable->name }}: {{ $history->historable->status }}
</p>
@endforeach
{{ dd(DB::getQueryLog()); }}
I need to be able to load the company names eagerly (in a single query) as it's a related model of the polymorphic relation models Product and Service.
I’ve been working on this for days but can't find a solution.
History::with('historable.company')->get() just ignores the company in historable.company.
What would an efficient solution to this problem be?
Solution:
It is possible, if you add:
protected $with = ['company'];
to both the Service and Product models. That way, the company relation is eager-loaded every time a Service or a Product is loaded, including when loaded via the polymorphic relation with History.
Explanation:
This will result in an additional 2 queries, one for Service and one for Product, i.e. one query for each historable_type. So your total number of queries—regardless of the number of results n—goes from m+1 (without eager-loading the distant company relation) to (m*2)+1, where m is the number of models linked by your polymorphic relation.
Optional:
The downside of this approach is that you will always eager-load the company relation on the Service and Product models. This may or may not be an issue, depending on the nature of your data. If this is a problem, you could use this trick to automatically eager-load company only when calling the polymorphic relation.
Add this to your History model:
public function getHistorableTypeAttribute($value)
{
if (is_null($value)) return ($value);
return ($value.'WithCompany');
}
Now, when you load the historable polymorphic relation, Eloquent will look for the classes ServiceWithCompany and ProductWithCompany, rather than Service or Product. Then, create those classes, and set with inside them:
ProductWithCompany.php
class ProductWithCompany extends Product {
protected $table = 'products';
protected $with = ['company'];
}
ServiceWithCompany.php
class ServiceWithCompany extends Service {
protected $table = 'services';
protected $with = ['company'];
}
...and finally, you can remove protected $with = ['company']; from the base Service and Product classes.
A bit hacky, but it should work.
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