laravel-mongodb：如何向两个现有集合添加外键？

Question

我正在使用laravel-mongodb(https://github.com/jenssegers/laravel-mongodb) 来操作mongodb中的数据，

我在 mongoDB 中有两个集合，它们是 books 和 categories。

稍后我会将它们导入mysql，所以我想先将它们与外键关联起来。

从 mongodb 获取它们：

public function getBooksAndCategories()
{
    $books = DB::connection('mongodb')->collection('books')->get();
    $categories = DB::connection('mongodb')->collection('categories')->get();
}

它们看起来像这样：

    $books = collect([
        ['_id' => 'xxx','name' => 'history book 1', 'category' => 'history'],
        ['_id' => 'xxx','name' => 'history book 2', 'category' => 'history'],
        ['_id' => 'xxx','name' => 'science book 1', 'category' => 'science'],
        ['_id' => 'xxx','name' => 'science book 2', 'category' => 'science'],
        ['_id' => 'xxx','name' => 'sociology book 1', 'category' => 'sociology'],
        ['_id' => 'xxx','name' => 'sociology book 2', 'category' => 'sociology'],
        ['_id' => 'xxx','name' => 'economics book 1', 'category' => 'economics'],
    ]);




    $categories = collect([
        ['_id' => 'xxx','category' => 'history'],
        ['_id' => 'xxx','category' => 'science'],
        ['_id' => 'xxx','category' => 'sociology'],
        ['_id' => 'xxx','category' => 'economics'],
    ]);

首先，我需要在$categories中添加一个id，结果是这样的：

    $newCategories = collect([
        ['_id' => 'xxx','category' => 'history','id' => 1],
        ['_id' => 'xxx','category' => 'science','id' => 2],
        ['_id' => 'xxx','category' => 'sociology','id' => 3],
        ['_id' => 'xxx','category' => 'economics','id' => 4],
    ]);

其次，我需要在集合$books中添加一个外键，结果是这样的：

    $newBooks = collect([
        ['_id' => 'xxx','name' => 'history book 1', 'category' => 'history','category_id' => 1],
        ['_id' => 'xxx','name' => 'history book 2', 'category' => 'history','category_id' => 1],
        ['_id' => 'xxx','name' => 'science book 1', 'category' => 'science','category_id' => 2],
        ['_id' => 'xxx','name' => 'science book 2', 'category' => 'science','category_id' => 2],
        ['_id' => 'xxx','name' => 'sociology book 1', 'category' => 'sociology','category_id' => 3],
        ['_id' => 'xxx','name' => 'sociology book 2', 'category' => 'sociology','category_id' => 3],
        ['_id' => 'xxx','name' => 'economics book 1', 'category' => 'economics','category_id' => 4],
    ]);

我不知道如何使用laravel-mongodb，有什么建议吗？

Answer 1

试试这样：

$last_new_id = 1;

foreach($categories as $category){
    $category->id = $last_new_id ;
    $last_new_id++;
}

foreach($books as $book){
    $book->category_id = $categories->where('category',$book->category)->first()->id
}