[英]Laravel eloquent - Eager loading nested relations
I have the following 3 tables:我有以下 3 个表:
Posts:帖子:
class Post extends Eloquent
{
public function comments()
{
return $this->hasMany(Comment::class,'post_id','id');
}
}
** Post data **
{
'id' : 1,
'title' : 'bla bla',
'created_at: 'some date'
}
Comments:注释:
class Comment extends Eloquent
{
public function comments()
{
return $this->belongsTo(Post::class,'id');
}
public function tags()
{
return $this->hasMany(Tag::class,'id','tags_ids');
}
}
** Comments data **
{
'id' : 322,
'active' : true
'post_id' : 1,
'created_at: 'some date',
'tags_ids' : [1,2,3]
}
Tags:标签:
class Tag extends Eloquent
{
public function tags()
{
return $this->belongsTo(Comment::class,'tags_ids');
}
}
** Tags data **
{
{'id' : 1,
'description' : 'some description1'
},
{'id' : 2,
'description' : 'some description2'
},
{'id' : 3,
'description' : 'some description3'
}
}
Post table has many comments and comments table has many tags associated with it.帖子表有很多评论,评论表有很多与之相关的标签。
How do i get all this tables together using eager loading?如何使用预先加载将所有这些表放在一起?
Something like :就像是 :
$post = Post::where('id',1)->with(['comments' => function($q) {
$q->with('tags');
}])->first();
but this query always returning empty response in the tags relationship.但是这个查询总是在标签关系中返回空响应。
What am i doing wrong?我究竟做错了什么?
The desired result is something like this:想要的结果是这样的:
{
'id' : 1,
'title' : 'bla bla',
'created_at: 'some date',
'comments':[{
'id' : 322,
'active' : true
'post_id' : 1,
'created_at: 'some date',
'tags_ids' : [1,2,3],
'tags' : [
{'id' : 1,'description' : 'some description1'},
{'id' : 2, 'description' : 'some description2'},
{'id' : 3,'description' : 'some description3'}
],
}
]
}
You can see that post contains comments inside it and comments contains tags relationship inside it as well.你可以看到帖子里面包含评论,评论里面也包含标签关系。
PS I am using the 'jenssegers/laravel-mongodb' package in my project and i am trying to do it without any raw expression. PS 我在我的项目中使用了 'jenssegers/laravel-mongodb' 包,我试图在没有任何原始表达式的情况下进行。
Thanks.谢谢。
You have defined your relationships wrong.你错误地定义了你的关系。 You have
tags_ids
as array in your comment model but instead you need many-to-many relationships for your tags.您的评论模型中有
tags_ids
作为数组,但您的标签需要多对多关系。 To implement this you have to define a new table comment-tag
:要实现这一点,您必须定义一个新表
comment-tag
:
comment-tag
comment_id - unsined big integer
tag_id - unsigned big integer
Then in you Comment
model modify tags
relationship like this:然后在您的
Comment
模型中修改tags
关系,如下所示:
class Comment extends Model
{
/**
* The tags that belong to the comment.
*/
public function tags()
{
return $this->belongsToMany('App\Tag');
}
}
The inverse of this relationship is:这种关系的逆是:
class Tag extends Model
{
/**
* The comments that belong to the tag.
*/
public function comments()
{
return $this->belongsToMany('App\Comment');
}
}
Then to eager load nested relationships, you may use "dot" syntax:然后急切加载嵌套关系,您可以使用“点”语法:
$post = Post::with(['comments', 'comments.tags'])->find(1);
See Many-to-Many relationship on Laravel docs for more info.有关更多信息,请参阅 Laravel 文档上的多对多关系。
you can use您可以使用
$post = Post::where('id',1)->with(['comments.tags'])->first();
it will load all the comments as well as comments.tags它将加载所有评论以及comments.tags
ref link https://laravel.com/docs/6.x/eloquent-relationships in link search Nested Eager Loading
链接搜索中的参考链接https://laravel.com/docs/6.x/eloquent-relationships
Nested Eager Loading
UPDATE: You must fix your db schema更新:您必须修复您的数据库架构
The table structure goes like this:
表结构是这样的:
- posts
- id
- title
- ...
- comments
- id
- active
- post_id
- created_at
- tags
- id
- description
- comment_id
- created_at
// App\Post
class Post extends Eloquent
{
public function comments()
{
return $this->hasMany(Comment::class,'post_id','id');
}
}
// App\Comment
class Comment extends Eloquent
{
public function post()
{
return $this->belongsTo(Post::class);
}
public function tags()
{
return $this->hasMany(Tag::class);
}
}
//App\Tag
class Tag extends Eloquent
{
public function comment()
{
return $this->belongsTo(Comment::class);
}
}
//...
$post = Post::with(['comments', 'comments.tags'])->find(1);
//...
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