来自不同模型的同一个表的多个关系

Question

I would like to have a simple and reusable way of sharing a relations with a specific table with different models. What I would like to do is the possibility to specify a table, with a foreign key column such as "parent_id" and then associate this table/model to several models in my app. Is there a way to do this in cake, and which is the best way? I guess I would need an additional column in this table, to specify which is the table every row is linked to, eg:

Table1

id 0 1 2 name name0 name1 name2 ...

Table2

id 0 1 2 name name0 name1 name2 ...

Common_table:

id 0 1 ... parent_id 0 0 parent_table Table1 Table2

I hope the explanation above made sense, thanks in advance!

Answer 1

yes

when you create a relationship you can also set the conditions

An example could be an application in which you have many models that can be commented, so they all are in a hasMany relationship with Comment Model.

You can create a column in comments table storing the name of the model being commented and a parent_id column storing the id.

So the comments table would tipically be something like

id | parent_id | model_name | comment_text         | user_id
---+-----------+------------+----------------------+-------
1  | 15        | Post       | I like this Post     | 3
1  | 15        | Post       | I like this Post too | 5
2  | 19        | Receipt    | This receipt is good | 3

in your Post Model you can do

public hasMany =array(
    'Comment' => array(
        'foreignKey' => 'parent_id',
        'conditions' => array('Comment.model_name' => 'Post')
    )

in your Receipt Model you can do

public hasMany =array(
    'Comment' => array(
        'foreignKey' => 'parent_id',
        'conditions' => array('Comment.model_name' => 'Receipt')
    )

and so on