1. Quynh Le, PHP Developer swiss IT bridge gmbh www.swissITbridge.ch An approach to implement Model classes in Zend Framework

6. Patterns (cont.) 2. Active Record class Employee extends ActiveRecord { //Storage logic methods public function insert(){} //Business logic methods public function calculateAge() { } } Pros : - Simple and easy to implement Cons : - Hard to test without database connection - Tight-coupling with Zend_Db_Table - Hard to change data source (Oracle, XML, SOAP, ...)

7. Patterns (cont.) 3. Data Mapper (Highly recommended) Separate Business logic & storage logic

8. Patterns (cont.) 3. Data Mapper (cont.) Patterns: - Lazy loading: Huge data fields, or relation objects - Identity map: Avoid to load the same object twice - Dependency injection: Initialize mapper objects

9. Patterns (cont.) 3. Data Mapper (cont.) Service Layer: - Place on the top of Domain Model and Data Mapper - Extend business logic - Forwards calls to Domain Model or Data Mapper

10. Patterns (cont.) 3. Data Mapper (cont.) Service Layer:

11. Patterns (cont.) 3. Data Mapper (cont.) Pros: - Can handle very complex business logic - Parallel implementation - Complete decoupling - Model is not aware of storage - Clean storage interface (implement different storages) - Can test without Database connection Cons: - Quite much code to write

12. Patterns (cont.) 3. Data Mapper (cont.) Sample code:

13. Reference Book: Patterns of Enterprise Application Architecture (Martin Fowler, 2002)

14. Thank you