电子商务不同的购物车项目数据库和模型设计

Question

I have a ecommerce site that has 2 types of products: books & seminars participations. They are different, and have different attributes. I am curious how would you model this in the DB and as models (since you cannot inherit multiple classes)

Right now i have something like: DB

products (id, name ....)
seminars (id, title, date ....)
cart (id, session_id ...)
cart (id, cart_id, type, id_model) the type is product OR seminar

as for models i have a

cart_item_abstract
cart_item_product -> cart_item_abstract
cart_item_seminar -> cart_item_abstract
cart_order_product -> cart_item_product
cart_order_seminar -> cart_item_seminar

But that means i have to duplicate some of the code required by order objects.

Answer 1

You should google for Inheritance Mapping", it all boils down to these choices:

• SINGLE_TABLE: Table-per-class-hierarchy, in this scenario the classes of one class erarchy are all mapped to one table.
• JOINED: Table-per-subclass, in this strategy each subclass will have its own table. To retrieve an object from the database the superclass and subclass tables are joined. This also applies to subclasses of subclasses.
• TABLE_PER_CLASS: table-per-class, each concrete class is stored in its own table. All properties (including inherited) are mapped to the table of the concrete class.

The selection depends on specific requirement - performance vs. simplicity, etc.