fit 2001 for week 4

Beginning analysis

1. Different models are used in the information system development:

a) Mathematical: formulas that describe technical aspects of the system

b) Descriptive: narrative memos reports or lists that describe aspects of the system

c) Graphical: diagrams and schematic representation of some aspect of the system

2. Overview of models used in analysis and design

a) Analysis phase activity named “define system requirements”

i. Logical models

ii. Provide detail without regard to specific technology.

b) Design phase

i. Physical models

ii. Provide technical details

iii. Extend logical models

3. Events: occurrences at a specific time and place, and trigger all system processing

Types of events:

a) External event: outside system, and initiated by external agent or actor

i. External agent wants something resulting in a transaction

ii. External agent wants some information

iii. Data changed needs to be updated

iv. Management wants some information

b) Temporal event: occurs as result of reaching a point in time, and based on the system deadline

i. Internal outputs needed

ii. External: statements, status, reports, bills, reminders

c) State: something inside system triggers processing nee

Event table:

Event	Trigger	Source	Use case	Response	Destination
	How does the system know the event occurred	The source of data entering the system	What does the system do when the event occurs?	What output is produced by the system?	What external agent gets the output

4. Things and system

Procedure for developing an initial list of things

a) Using the event table and information about each event, identify all nouns about the system

b) Using other information from existing systems, current procedures and current reports or forms, add items or categories of information needed.

c) Refine list and record assumptions or issues to explore

Characteristics of things:

a) Relationship

b) Attribute: a piece of information about a thing

Objects:

Objects do the work in the system and store information in OO approach, and objects have behaviors and attributes.

An object is encapsulated – a self-contained unit.

The class diagram

5. UML

OO system requirements are specified and documented through process of building models, and system development process starts with identification of events and things.

Events are business processes that new system must addressed.

Things are problem domain objects involved in business process.