在 CakePHP 的一个字段中具有多个 id 的表关联

Question

I am using CakePHP and I have 2 tables, Documents and Download, on the Download table I have a field: Document_id, making the association with the model works fine, but sometimes i have in Document_id a field like this "2,10,12", How can I associat the tables?

Answer 1

You shouldn't store multiple ids in one field (unless you're intentionally denormalizing your database, but then you wouldn't be asking this question).

The "proper" way to do this is use a 3rd table called a linking table. eg "documents_downloads", to store the download_ids with matching document_ids.

Download hasMany DocumentDownload
DocumentDownload belongsTo Download & Document
Document hasMany DocumentDownload

The simplest way to implement this is using Cake's "hasMany through (The Join Model)"

See section of the Cakebook: http://book.cakephp.org/2.0/en/models/associations-linking-models-together.html#hasmany-through-the-join-model