Laravel 如何加入一对多的关系表
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Laravel how to join one to many relationship tables
提问by Hax0r
I am using Laravel 5.5 and I want to display list of data by joining tables that have one to many relationship.
我正在使用 Laravel 5.5，我想通过连接具有一对多关系的表来显示数据列表。
Currently, I do this by going through the loop and make queries to retrieve data. This way, I think, is very inefficient, because if I were to display 1000 rows of data record, I will have to go 1000 loops to append other data with one-to-many relationship.
目前，我通过循环执行此操作并进行查询以检索数据。这种方式，我认为是非常低效的，因为如果我要显示 1000 行数据记录，我将不得不循环 1000 次以一对多关系附加其他数据。
I am thinking to get around this problem using cache but it does not seem to solve fundamental problem.
我正在考虑使用缓存来解决这个问题，但它似乎并没有解决根本问题。
For more understanding I have shared tables that I want do join as below.
为了获得更多的理解，我共享了我想要加入的表，如下所示。
Post Table
邮政桌
| id | comment_id | status |
|----|------------|--------|
| 1 | 1 | 0 |
| 2 | 2 | 0 |
| 3 | 3 | 1 |
| 4 | 4 | 0 |
| 5 | 5 | 1 |
| 6 | 6 | 1 |
Comment Table
评论表
| id | order_id | content |
|----|----------|----------|
| 1 | 1 | hi |
| 2 | 1 | hellow |
| 3 | 1 | yes |
| 4 | 1 | okay |
| 5 | 2 | bye |
| 6 | 2 | good bye |
If I were to join Table Postwith Table Comment, because they have one to many relationship, rows would not match. How would I join these two tables to show the list of post with comments?
如果我将 TablePost与 Table连接起来Comment，因为它们有一对多的关系，所以行将不匹配。我将如何加入这两个表以显示带有评论的帖子列表？
Sample List Controller
样本列表控制器
/**
* @param Request $request
* @return \Illuminate\Http\JsonResponse
*/
public function list(Request $request)
{
$vaildData = $request->validate([
'comment_id' => 'numeric',
]);
$posts = new PostModel;
$posts->find(1);
$displayPosts = [];
foreach ( $posts->find(1)->get() as $post ) {
$displayPosts->comments = $post->comment()->get();
}
return $displayPosts;
}
Post Modelnamespace App\Model\Post;
Post 模型命名空间 App\Model\Post;
use SoftDeletes;
use Illuminate\Database\Eloquent\Model;
class Post extends Model
{
public function comments()
{
return $this->hasMany('App\Model\Post\Comment', ‘post_id', 'id');
}
}
回答by Sohel0415
Use with()for eager loading your comments.
使用with()来急切地加载您的评论。
$posts = PostModel::with('comments')->find($id);
So your function will be like-
所以你的功能会像-
public function list(Request $request)
{
$vaildData = $request->validate([
'comment_id' => 'numeric',
]);
$posts = PostModel::with('comments')->find(1);
return $displayPosts;
}
You can filter your comments with comment_id using whereHas()like the following-
您可以使用whereHas()使用 comment_id 过滤您的评论，如下所示-
$comment_id = $request->input('comment_id');
$posts = PostModel::with('comments')->whereHas('comments', function ($query) use($comment_id)
{
$query->where('id', '=', $comment_id);
})->find(1);
回答by Tommy Lee
https://laravel.com/docs/5.1/eloquent-relationships
https://laravel.com/docs/5.1/eloquent-relationships
Firstly, you may refer to this documentation.
首先，您可以参考此文档。
To setup one-to-many relationship for Post and Comment table:
为 Post 和 Comment 表设置一对多关系：
- A Post has Many Comments
- So in you Comment table there should be a column named post_id
- Inside your Post.php
- 一个帖子有很多评论
- 所以在你的 Comment 表中应该有一个名为 post_id 的列
- 在你的 Post.php 里面
public function comments()
{
return $this->hasMany('App\Comment');
}- Inside your controller
- 在你的控制器里面
public function list(Request $request){
$posts = Post::where('id', 1)
->with('comments')
->get()
return $posts;
}回答by Saengdaet
public function list(Request $request, $id)
public function list(Request $request, $id)
{
{
$vaildData = $request->validate(['comment_id' => 'numeric',]);
$vaildData = $request->validate(['comment_id' => 'numeric',]);
$posts = PostModel::find($id);
return $posts->comments;
}
}
try this... Hope this can help you
试试这个...希望这可以帮助你
or you can try like this
或者你可以像这样尝试
public function list(Request $request, $id)
public function list(Request $request, $id)
{
{
$vaildData = $request->validate(['comment_id' => 'numeric',]);
$vaildData = $request->validate(['comment_id' => 'numeric',]);
$posts = PostModel::find($id)->comments()->get();
return $posts;
}
}
回答by sysummer
public function list(Request $request)
{
$vaildData = $request->validate([
'comment_id' => 'numeric',
]);
$posts = new PostModel;
$results = $posts->find(1)->with('comments')//comments is the function name you defined in the App\Model\Post
return resurts;
}
collection results contain the infomation of the post and another extra comment collection that belong to the post
收藏结果包含帖子的信息和属于该帖子的另一个额外评论集合
