Laravel雄辩的嵌套查询 [英] Laravel Eloquent nested query

问题描述

我正在与Laravel合作，陷入困境.我有以下型号:

I was working with Laravel and got stuck in a situation. I have following models:

• 类别
• 产品
• CategoryProduct

CategoryProduct保存有关哪个产品属于哪个类别(一个产品可能属于多个类别)的信息.

CategoryProduct holds the information about which product belongs to which category (a product may belong to multiple categories).

现在，当我想加载属于特定类别的所有产品时，我需要在卡住的Product和CategoryProduct上运行查询.

Now, when I want to load all products belonging to a particular category, I need to run query on Product and CategoryProduct which is where I'm stuck.

我尝试了以下方法，但未成功:

I gave it the following try but was unsuccessful:

$products = Product::where('status', '=', 'active')
->where('category_id', '=', $category_id)
->take($count)
->skip($skip)
->get();

很明显，它会说category_id不是列.

Obviously, it will say that category_id is not a column.

这是我的数据库&模型结构:

Here is my DB & Model structure:

id， 姓名， 等

id， 姓名， sku， 等

id, name, sku, etc.

id， product_id，(Product.id的外键) category_id，(Category.id的外键) 等

id, product_id, ( Foreign key to Product.id ) category_id, ( Foreign key to Category.id ) etc.

class Product extends Eloquent {

protected $table = 'products';

protected $hidden = array();

    public static $rules = array('name' => 'required|min:3');

}

类别模型

class Category extends Eloquent {

protected $table = 'categories';

public static $rules = array('name' => 'required|min:3');

}

类别产品型号

<?php

class CategoryProduct extends Eloquent {

protected $table = 'category_products';

public function product()
{
    return $this->belongsTo('Product');
}

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

更新

对此有一个新问题

Update

A new question on this

我正在尝试展示产品.如果未传递类别(值是-1)，则我将显示所有产品，否则将显示传递的类别中的产品.

I'm trying to display products. If category is not passed (value is -1), then I will show all products, otherwise I will show products from the passed category.

现在，当我显示所有产品时，这些产品可能已经存在于一个类别中.我要显示类别中已经存在的产品的复选框.我正在做这样的事情:

Now, when I show all products, those products may already exist in a category. I want to display ticked checkbox for products that are already in a category. I'm doing something like this:

if($category_id==-1)
        $products = Product::where('status', '=', 'active')->take($count)->skip($skip)->get();
    else{
        $products = Product::whereHas('categories', function($q) use ($category_id)
        {
            $q->where('category_id', $category_id);
        })->where('status', 'active')
            ->take($count)
            ->skip($skip)
            ->get();
    }

表 category_products 具有product_id，category_id作为列.

The table category_products have product_id, category_id as columns.

现在，查询:

$ products = Product :: where('status'，'='，'active')-> take($ count)-> skip($ skip)-> get();

$products = Product::where('status', '=', 'active')->take($count)->skip($skip)->get();

将仅从产品表中选择产品.如果我在 category_products 中检查每种产品是否存在，那么对于大量产品的数据库查询将太多.

will pick products only from products table. If I check each product for its existence in category_products, then there will be too many database queries for large number of products.

任何想法，如何实现.我希望我能解决我的情况.谢谢

Any idea, how to achieve this. I hope I was able to clear my situation. Thanks

推荐答案

除非您除了product_id和category_id之外还有其他字段指向其他关系，否则CategoryProduct模型应该不是必需的.

The CategoryProduct model should not be necessary unless you have additional fields besides product_id and category_id which point to other relationships.

在Category和Product模型上建立关系的方法是必需的.

What is necessary are the methods for setting up the relationship on the Category and Product models.

在Category中，添加关系函数...

In Category, add the relationship function...

public function products()
{
    return $this->belongsToMany('Product', 'category_products');
}

在您的Product模型中，对类别执行相同的操作.

In your Product model, do the same for categories.

public function categories()
{
    return $this->belongsToMany('Category', 'category_products');
}

然后，您可以使用关联方法和whereHas()

Then you can query for your active products that belong to that category using your relationship method and whereHas()

$products = Product::whereHas('categories', function($q) use ($category_id)
{
    $q->where('id', $category_id);
})->where('status', 'active')
->take($count)
->skip($skip)
->get();

这篇关于Laravel雄辩的嵌套查询的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！