Laravel 5.2 |查询多对多 [英] Laravel 5.2 | query many to many to one

问题描述

目前，我正在开展一个多域名和语言项目，其中视频被重复使用不同的标题和描述。

Currently I am working on a multi domain and language project where videos are reused with different titles and description.

我与这个问题相关的表与关系像

My tables that are relevant to this question with relations look like

posts    >-    videos    >-    videos_tags    -<    tags
id             id              id                   id
domain_id                      video_id             
video_id                       tag_id

当然，我已经创建了模型：Post，Video和Tag与所有必需的关系。

Of course I have created the models: Post, Video and Tag with all the required relationships.

我正在尝试的事情是通过我的标签模型获取所有的帖子，维护分页（）功能。

The thing I am trying is to get all the posts by my Tag model and maintaining the pagination() functionality.

我可以通过视频模型获取链接到帖子的所有标签。但是，当我尝试逆向的方式时，我似乎并没有保持分页（）功能。我已经尝试了很多，但似乎找不到正确的解决方案。

I am able to get all tags linked to a Post through a Video model. However when I am trying an inverse way I don't seem to keep the pagination() functionality. I have tried a lot but can't seem to find the right solution.

最近（我想）我一直在使用这段代码：

The closest (I think) I have been with this piece of code:

// App\Models\Tag
public function posts()
{
    $posts = [];

    foreach ($this->videos as $video)
    {
        foreach ($video->posts as $post)
        {
            if (!array_key_exists($post->id, $posts)) $posts[$post->id] = $post;
        }
    }


    return \Illuminate\Database\Eloquent\Collection::make($posts);
}

我在寻求答案时遇到的任何建议或文章都受到欢迎： ）

Any suggestions or articles I have missed during my quest for the answer are welcome :)

推荐答案

直接问了这个问题后，我有一个尤里卡时刻，找到了解决方案。这样做的方法不是通过标签模型获取Post模型，而是通过Post模型本身。

Directly after asking this question I had an eureka moment and found the solution. A way to do this is not by getting the Post models by the Tag model but through the Post model itself.

这就是我所做的：

// App\Models\Tag
public function posts()
{

    return Post

            ::select('posts.*')

            ->join('videos', 'posts.video_id', '=', 'videos.id')

            ->join('videos_tags', 'videos.id', '=', 'videos_tags.video_id')

            ->join('tags', 'videos_tags.tag_id', '=', 'tags.id')

            ->where('tags.id', $this->id);

}

这解决了查询多对多到一个问题关系和维护征集功能之前执行查询。

This solves the problem of querying a many to many to one relationship and maintaining eloquents functionalities before the query is executed.

这篇关于Laravel 5.2 |查询多对多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！