1. Database Development
(8 May 2017)

2. Overview Database Life Cycle 3-Tier Architecture for Database Design
Database Design Strategies
Centralized Database vs Decentralized (Distributed) Database
Selection of DBMS

3. System Development Life Cycle
System Development Life Cycle (SDLC) is the process of developing a computer system.
The SDLC are separated in five phases:
Planning
Analysis
System Design
Implementation
Maintenance
It is an iterative process rather than sequential process.

4. Database Life Cycle (DBLC)
Database Life Cycle is the process of developing a database system.
It consists of SIX phases:
Initial study
Database Design
Implementation and Data loading
Testing & evaluation
Operation / deployment
Maintenance & Evolution

5. 3-Tier Architecture Design
3-Tier Architecture Design is a client-server architecture in developing a database system.
The architecture is separated into 3 layers:
External Layer
Logical / Conceptual Layer
Physical Layer

6. External Level This is the application level of the database system.
This is where the user will view the different forms and report generated from database.
The people involves in this level is application programmer and End user.
Example for this level is the webpages that have access to a database.

7. Conceptual Level This level is where the database is design.
It defines the characteristics of the data to be stored and also the relationship among the data.
People involves in this level are database designer.
Example of output of this level is the Entity Relationship Diagram (ERD)

8. Physical Level
This level is the actual database where the data is stored.
The type of DBMS and the physical hardware used as the database is also decided here.
People involves in this level are the database administrators.
The example of this level is the internal scheme of the database, The DBMS used and also the physical data server.

9. Provide mapping and independence User Data
DBMS and OS
End User /
Application Developer
Database Designer
Database
Administrator
Role or Personel Involved
Physical level

10. Database Design Strategies
Two ways of designing a database:
Top-Down Approach
Identify each entity / table
Identify every attributes for each entity / table
Identify relationship
Bottom-Up Approach
Identify all the data elements
Group / classify the data elements as attributes for entity / table
Form entity or table

11. Centralized database VS Decentralized database
all the data are save in a single location.
Pro: it is easy to manage.
Cons: once the database is corrupted or damaged, high risk of downtime and data loss.
Decentralized database:
Also known as distributed database.
The database can be separated into several parts based on entity or functionality and store in different devices or locations.
Or having multiple copies in different devices or locations.
Pro: lower risks of total down time for the system and data loss.
Cons: Complex and hard to handle.

12. DBMS Software Selection
Critical to information system’s smooth operation
Common factors affecting purchasing decisions:
Cost
DBMS features and tools
Underlying model
Portability
DBMS hardware requirements

13. Question?