如何在 Laravel 上更新数据透视表?

问题描述

我使用 Laravel 5.3

I use laravel 5.3

我有 3 个表:表产品、表类别和表 products_categories

I have 3 table : table product, table category and table products_categories

表产品:id、名称等

表格类别:id、名称等

table category : id, name, etc

表 products_categories : id, product_id, category_id

table products_categories : id, product_id, category_id

在模型产品中，我有这样的方法:

In model product, I have method this :

public function categories()
{
    return $this->belongsToMany(Category::class, 'products_categories', 'product_id', 'category_id')
                ->withPivot('id')
                ->withTimestamps();
}

所以 1 个产品有多个类别

So 1 product have many category

我的代码是这样的

例如 $param['category'] 像这样:

For example $param['category'] like this :

数组 (['category1'] => 4['category2'] => 11['category3'] => 18 )

Array ( ['category1'] => 4 ['category2'] => 11 ['category3'] => 18 )

$product_id = 1

$product_id = 1

foreach ($param['category'] as $category) {
    Product::find($product_id)
        ->categories()
        ->attach(
            $category, 
            []
        );
}

它用于在数据透视表上添加类别并且它有效

It used to add category on the pivot table and it works

但是如果我更新数据透视表上的类别，它就不起作用

But if I update category on the pivot table, it does not work

我是这样尝试的:

比如之前这样编辑过的分类

For example the category previously edited like this

$param['category'] =

$param['category'] =

数组 (['category1'] => 5['category2'] => 12['category3'] => 19 )

Array ( ['category1'] => 5 ['category2'] => 12 ['category3'] => 19 )

$product_id = 1

$product_id = 1

以及更新数据透视表数据的代码如下:

And the code to update data on the pivot table like this :

foreach ($param['category'] as $category) {
    Product::find($product_id)
           ->categories()
           ->wherePivot('product_id', $product_id)
           ->updateExistingPivot($category, ['category_id' => $category]);
}

未成功更新字段类别

我该如何解决?

推荐答案

尝试使用 sync() 函数

Try to use the sync() function

Product::find($product_id)->categories()->sync($array_of_categories_id)

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