1. DAL, Three-tier architecture
Lecture 3

2. Objectives Tiered application design
Components of three-tier architecture
DAL (DB Managers)

3. Tiered application design
multi-tier architecture (often referred to as n-tier architecture) is a client–server architecture in which the presentation, the application processing, and the data management are logically separate processes. (Wikipedia.com)

4. Tiered application design
Benefits:
Task separation
Code independence
Code reuse
Performance/scalability

5. Three-tier architecture
GUI
GUI
GUI
Business Logic
DAL

6. Tiered application design
GUI:
Graphical User Interface
Application can have several GUI types:
windows forms,
web application,
smart devices etc.

7. Tiered application design
GUI:
Technologies:
Win32, WPF
Web: ASP.Net (Web Pages, MVC), Silverlight
Web-services, WCF

8. Tiered application design
Business Logic:
POJO – plain old java objects.
Set of classes abstracting real business case

9. Tiered application design
DAL:
Data Access Layer
Set of classes providing access to persistent storage (RDBMS, flat files etc.)
ORM

10. ORM Microsoft Third-party LINQ to SQL Entity framework SQL Metal
NHibernate
DataObjects.Net
and many more

11. DAL – Manager approach Manager class per DB table Methods:
Insert(inst as BusinessObject)
Update(inst as BusinessObject)
Delete(id as Integer)
GetById(id as Integer)
GetAll() as ArrayList

12. DB access recap
OleDbConnection
OleDbCommand
OleDbDataReader

13. This semester we will use
SqlCeConnection
SqlCeCommand
SqlCeDataReader

14. The End