Laravel：如何使用多个数据透视表关系

Laravel: How to use multiple pivot table relationships

提问by Pwnball

I'm new to defining relationships and frameworks all together, I'm just used to raw SQL. Did my homework (google + Laravel documentation) but I think I'm just not understanding it properly.

我是一起定义关系和框架的新手，我只是习惯了原始 SQL。做了我的作业（google + Laravel 文档），但我想我只是没有正确理解它。

Heres is the relevant information: User Table:

以下是相关信息： 用户表：

Table: Users
id       - int (auto increment)
username - varchar

Challenges Table:

挑战表：

Table: Challenges
id    - int (auto increment)
name  - varchar

User_challenge_links

User_challenge_links

Table User_challenge_links
id                          - int (auto increment)
user_id                     - int
challenge_sub_categories_id - int

Challenge_sub_categories

Challenge_sub_categories

Table Challenge_sub_categories
id                - int (auto increment)
category_id       -
sub_category_id   -
challenge_id      -

So my goal.. user->challenges.

所以我的目标.. 用户-> 挑战。

class User extends Eloquent
{
    protected $table = "users";

    public function challenges() {
        // get user-> challenges
    }
}

The relationships:

关系：

• A user has many User_challenge_links
• A User_challenge_link has a challenge_sub_categories_id (thus a challenge_sub_category)
• A challenge_id from challenges_sub_categories matches a challenge in the challenges table

• 一个用户有很多 User_challenge_links
• User_challenge_link 有一个challenge_sub_categories_id（因此是challenge_sub_category）
• 来自challenge_sub_categories 的challenge_id 匹配挑战表中的挑战

Any help, even pointing me in the right direction will be much appreciated!

任何帮助，甚至将我指向正确的方向，将不胜感激！

Edit:example data: Users Data

编辑：示例数据：用户数据

Users
id    name
1     "Sjaak"
2     "Henk"

Categories Data id name 1 "Foo" 2 "Bar"

类别 数据 id 名称 1 "Foo" 2 "Bar"

Sub_categories Data id name 1 "SubFoo" 2 "SubBar"

Sub_categories 数据 id 名称 1 "SubFoo" 2 "SubBar"

Challenges Data id name 1 "Swing dat Foo" 2 "Bar all the things" 3 "Foo The Bars"

挑战 数据 ID 名称 1 “Swing dat Foo” 2 “Bar all the things” 3 “Foo The Bars”

Challenge_sub_categories Data

Challenge_sub_categories 数据

id   category_id    sub_category_id    challenge_id
1    1              1                  1
2    2              1                  1
3    1              2                  2
4    2              1                  3
5    2              2                  2

User_challenge_links Data

User_challenge_links 数据

id     user_id      Challenge_sub_categories_id
1      1            1
2      1            3
3      2            2
4      2            3
5      2            4

Dataflow:
A user can create categories or use existing ones and link challenges to them (existing or new). However, a user can also choose to use a subcategory, which he then links to a category and link challenges to that instead.
So, a category is mandatory, but a sub_category isn't. If however a sub_category is used (again.. existing or new) the challenge will be connected to that subcategory.

数据流：
用户可以创建类别或使用现有类别并将挑战链接到它们（现有的或新的）。但是，用户也可以选择使用子类别，然后将其链接到一个类别并将挑战链接到该类别。
因此，类别是强制性的，但 sub_category 不是。然而，如果使用 sub_category（再次......现有的或新的），挑战将连接到该子类别。

Note:A subcategory CAN be connected to multiple categories

注意：一个子类别可以连接到多个类别

category - House
    sub_category - Cleaning
         Challenge - getting special soap

category - Car
    sub_category - Cleaning
        Challenge - getting special soap

category - Showering
    Challenge - getting special soap

These are some possible situations

这些是一些可能的情况

回答by lagbox

This setup should get you going. I tried to keep the naming as simple as possible.

这个设置应该让你开始。我试图保持命名尽可能简单。

users
    id
    username

challenge_user
    user_id
    challenge_id

challenges
    id
    name
    topic_id      
    category_id

topics
    id
    name

categories
    id
    name

Defining your Eloquent Models

定义你的 Eloquent 模型

class User extends Eloquent {
    public function challenges() {
        return $this->belongsToMany('Challenge');
    }
}

class Challenge extends Eloquent {
    public function users() {
        return $this->belongsToMany('User');
    }
    public function topic() {
        return $this->belongsTo('Topic');
    }
    public function category() {
        return $this->belongsTo('Category');
    }
}

class Topic extends Eloquent {
    public function challenges() {
        return $this->hasMany('Challenge');
    }
}

class Category extends Eloquent {
    public function challenges() {
        return $this->hasMany('Challenge');
    }
}

Using your Eloquent Models ... just some exmaples of what you can do.

使用你的 Eloquent 模型......只是你可以做的一些例子。

// Collection of all Challenges by Topic name
Topic::with('challenges')->whereName($topic_name)->first()->challenges;

// Collection of all Challenges by Category name
Category::with('challenges')->whereName($category_name)->first()->challenges;

// Collection of all Users by Challenge id
Challenge::with('users')->find($challenge_id)->users;

// Collection of Users with atleast 2 Challenges
User::has('challenges', '>', 1)->get();

// Attach Challenge to User
$user = User::find($id);
$user->challenges()->attach($challenge_id);

// Assign a Topic to a Challenge
$challenge = Challenge::find($challenge_id);
$topic     = Topic::find($topic_id);

$challenge->topic()->associate($topic);
$challenge->save();

References and suggested reading:

参考资料和建议阅读：

Laravel Eloquent RelationshipsbelongsTobelongsToManyhasMany

Laravel 雄辩的关系belongsTobelongsToManyhasMany

Querying relationsModel::has()

查询关系Model::has()

Eager LoadingModel::with()

急切加载Model::with()

Dynamic Properties for Accessing RelationsResolve $model->relationship

访问关系解析的动态属性$model->relationship

Inserting related Modelsattach()associate()

插入相关模型attach()associate()

Query Scopes

查询范围

Working with Pivot tablesIf you need to retrieve extra data from the pivot table.

使用数据透视表如果您需要从数据透视表中检索额外数据。