Putting into practice

Question 1

What’s the guideline for which pattern to use in developing an application

Answer 1

1- Option layer by layer
2- Option depending on the technological platform

Question 2

Main options in the domain layer

Answer 2

Transaction Script
– Best for simple apps
– Procedural logic, easy but not scalable
Table Module
– For moderate complexity
– Logic tied to DB tables, OK for form-based apps
Domain Model
– For complex/extensible logic
– Full OOP, harder to map to DB but powerful

Question 3

Main options for the data layer:

Answer 3

It depends on the choice of the domain layer
Transaction Script → Row Data Gateway or Table Data Gateway
(+ Optimistic Offline Lock if editing before saving)

Table Module → Table Data Gateway
(+ Unit of Work for concurrency)

Domain Model

Simple: → Active Record

Complex: → Data Mapper

Question 4

Main options for presentation layer

Answer 4

• Use client side frameworks for interactive apps
  -Use server side rendering for simpler HTML based apps

Question 5

When is MVC used?

Answer 5

Model View Controller is used in both cases,
Model in Domain layer (handles data & logic)

View & Controller in Presentation layer

Controller:
- Page controller-> simple document
oriented sides (static + dynamic)

 - Front controller -> more complex and 
 interactive interfaces, both client and 
 server side

View:
- Template view: common, simple, server
page + client side
- Transform view: with XML input, allows
output formats
- Two step view: unusual, for very
complex view with different output
formats