The main question about OOP

Question

I often have the same problems when I have to create my own class for a web application. Requirements: - supported (for example, without copying) - the layers are completely separated (the business layer does not need to know which method is used for the data layer) - high performance: do not load useless data.

First, I have a table with all my clients and their addresses: Code:

Customer
--Id
--Name
--Address
----City
----ZC
----Street

Now I need a table (on another page) with all my clients and the books they bought, I have several options:

1 / I create a new class:

The code:

CustomerWithBooks
--Id 
--Name
--Books[]
----ID
----name

PRO: I load only useful data CONS: I create my class after my user interface, and there is a copy.

2/ Books [] . PRO: , CONS: . , : , , , , DAL , .

3/ : :

ClientBase
--ID
--Name

ClientWithBooks : ClientBase
--Books[]

ClientWithAdress : ClientBase
--Address

PRO: , CONS: , ?

4/?? ,

Answer 1

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• , Order.

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Answer 2

2 3, , . , , , , , , , , . , , . - , . , , .

, 1. , , CustomerBook, , . , scenerio.

Answer 3

Customer .

Bookshelf
--Books[]

, Customer , , . PHP-:

class BookshelfFactory {
  public static function getBookshelf(Customer $customer) {
     // perform some fetching here
     return $bookshelf;
  }
}

Answer 4

OOA & D. ( ). OOA & D , ( , ). :

Customer
+getBooks():List<Book>
+getAddress():Address

Answer 5

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