Week 3: Database Design

Information System

A system that provides for data collection, storage, and retrieval; facilitates the transformation of data into information; and manages both data and information.

Information System Parts

• Hardware

• the DBMS and other software, database(s),

• People

• Procedures

System Analysis

The process that establishes the need for an information system and its extent.

System Development

The process of creating an information system

Database Development

The process of database design and implementation.

System Development Life Cycle (SDLC)

This is a cycle that traces the history of an information system. It provides the big picture within which database design and application development can be mapped out and evaluated.

SDLC Planning Phase

This phase yields a general overview of the company and its objectives.

SDLC Analysis Phase

In this phase, problems are examined in greater detail. A macro analysis must be made both of individual needs and organizational needs

SDLC Detailed System Design Phase

In this phase, the designer completes the design of the system’s processes. The design includes all the necessary technical specifications for the screens, menus, reports, and other devices that might help make the system a more efficient information generator.

SDLC Implementation Phase

The hardware, the DBMS software, and application programs are installed, and the database design is implemented.

SDLC Maintenance Phase

Almost as soon as the system is operational, end users begin to request changes in it. Those changes generate system maintenance activities.

Corrective Maintenance

The maintenance used in response to system errors.

Adaptive Maintenance

This maintenance is needed due to changes in the business environment.

Perfective Maintenance

This maintenance is used to enhance the system.

Purpose of Database Initial Study

1. Analyze the company situation

2. Define problems and constraints

3. Define objectives

4. Define scope and boundaries

Database Initial Study - Analyze the company situation

It describe the general condition in which the company operates, its organizational structure, and its mission.

Database Initial Study - Define problems and constraints

The designer has both formal and informal sources of information.

Database Initial Study - Define Objectives

The designer’s job is to make sure that his or her database system objectives correspond to those envisioned by the end user(s).

Database Initial Study - Define Scopes and Boundaries

It defines the extent of the design according to operational requirements.

Database Design

It focuses on the design of the database model that will support company operations and objectives.

DBLC - Implementation and Loading

The implementation of design specification. This includes creation of tables, attributes, domains, views, indexes, security constraints and storage and performance guidelines.

DBLC - Testing and Evaluation

The DBA test and fine-tunes the database to ensure that is performed as expected.

DBLC - Operation

Once the database has passed the evaluation stage, it is considered as operational.

DBLC - Maintenance and Evolution

The database administrator must be prepared to perform routine maintenance activities within the database.

Business Rule

A brief description of a policy, procedure, or principle within an organization (e.g., "A customer may generate many invoices").