如何在CakePhp中建立三元关系？ [英] How to Model Ternary Relationship in CakePhp?

问题描述

页表

（1）

|

|

（*）

User_Moderate_Page（*）-----------（1）Access_level表

（*）

|

|

（1）

用户表

Page table
(1)
|
|
(*)
User_Moderate_Page (*)----------- (1)Access_level table
(*)
|
|
(1)
User table

如何在CakePhp中建立这样的三元关系？
用户到页面可以使用hasBelongtoMany关系建模。但是User_Moderate_page只是一个关联表，我是否应该在Cake中为User_Moderate_Page编写一个模型？

How do i Model such a ternary relationship in CakePhp? User to Page can be modelled using the hasBelongtoMany Relationship. But User_Moderate_page is just an association table, should I even write a Model for User_Moderate_Page in Cake?

推荐答案

它与通用表：
假设你有3个表 - 第一，秒，第三 - 每个都有主键'id'。

Let me generalize it by describing it with generic tables: Lets say you have 3 tables - firsts, seconds, thirds - each with primary keys 'id'.

让你的连接表每个主表使用外键调用firsts_seconds_thirds：

let your join table be called 'firsts_seconds_thirds' with foreign keys to each main table:

• first_id


• second_id


• third_id


• <此关联表的其他字段>

• first_id
• second_id
• third_id
• <additional fields of this association table>

通常我们定义表之间的HABTM关系，在这种情况下，我们需要为连接表创建一个蛋糕模型 - 让它叫 FirstsSecondsThird （通过cakePhp的命名约定）

usually we define HABTM relationships between tables, in this case we need to create a cake model for the join table - lets call it FirstsSecondsThird (By cakePhp's naming conventions)

您需要定义的模型之间的关系是：

The relationship between models you need to define is:

• 首先 hasMany FirstsSecondsThird


• 第二有多少 FirstsSecondsThird


• 第三有多少 FirstsSecondsThird


• FirstsSecondsThird belongsTo 第一，第二，第三

• First hasMany FirstsSecondsThird
• Second hasMany FirstsSecondsThird
• Third hasMany FirstsSecondsThird
• FirstsSecondsThird belongsTo First,Second,Third

a href =http://book.cakephp.org/2.0/en/models/associations-linking-models-together.html#hasmany-through =nofollow>一起链接模型

同样的代码：

The need for this is explained here - Associations: Linking Models Together
Code for the same:

class First extends AppModel {    
    public $hasMany = array(
        'FirstsSecondsThird'  => array(
            'className' => 'FirstsSecondsThird',
            'foreignKey' => 'first_id'
        )
    );
}

//Same for classes 'Second' and 'Third'

class FirstsSecondsThird extends AppModel {
    public $belongsTo = array(
        'First' => array(
            'className' => 'First',
            'foreignKey' => 'first_id'
        ),
        'Second' => array(
            'className' => 'Second',
            'foreignKey' => 'second_id'
        ),
        'Third' => array(
            'className' => 'Third',
            'foreignKey' => 'third_id'
        )
    );
}

这些模型是完全设置，但现在插入/更新/ / join表应该正确或者没有用。
Model :: saveMany（）和 Model :: saveAssociated（）等等需要使用。阅读它此处。
您还需要考虑这些连接表的ON DELETE RESTRICT / CASCADE，并对它们进行适当的建模。

The models are perfectly setup, but now inserting/updating/deleting from the main/join table should be done correctly or they are of no use. Model::saveMany() and Model::saveAssociated(), using the option 'deep' etc. need to be used. Read about it here.
You also need to think about ON DELETE RESTRICT/CASCADE for these join tables and model them appropriately.

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