UML and Developmental Models Flashcards
1
Q
What does UML ,UCD and DFD stand for?
A
- Unified Modelling Language
- Use Case Diagram
- Data Flow Diagram
2
Q
What is UML?
A
- an analysis tool which is used to illustrate / model computer applications
3
Q
What is a Use Case Diagram?
A
- a method of describing how a user interacts with a system
4
Q
What is an actors in a UCD?
A
- An actor is the term used to denote a role that is external to the system.
- The actor is often a person or organisation
4
Q
What is an actors in a UCD?
A
- An actor is the term used to denote a role that is external to the system.
- The actor is often a person or organisation
5
Q
What is a use case in a UCD?
A
- A use case is a representation of a function within the system.
6
Q
What is the system boundary?
A
- a system boundary is a rectangle that is draw around all of the use case symbols and represents the confines of the system.
- actors are outside the system boundary
7
Q
What is an association / communication in UCD?
A
Lines showing the link between a use case and actor(s). A use case can be carried out by many actors and an actor may carry out many use cases
8
Q
What is a <>
A
- Dotted lines with arrowheads and the text “<>” showing the links between use cases.
- Indicates that the functionality of a use case is used in another use case
9
Q
What is an <>
A
- dotted line with arrowheads and the text “<>” showing that the functionality of a use case contributes to the functionality of another use case
- conditional
10
Q
Steps in creating a UCD?
A
- identify actors
- draw system boundary
- identify use cases
- draw connections between use cases
11
Q
What is a DFD?
A
- DFDs provide a method by which the movement of data through a system can be visually represented
12
Q
What is an Entity?
A
- AN entity is a person, agent or company outside the organisation being examined that provides some data to the system or receives some information
13
Q
What is Data Flow?
A
- A data flow is represented by an arrow from one symbol to another and generally begins with a verb.
14
Q
What is a data store?
A
- A data store symbol represents a storage location within the organisation
15
Q
What is a process?
A
- A process symbols is used to describe any activity that transforms data and generally begins with a verb
16
Q
Name the primary DFD rules and conventions?
A
- Data cannot flow between:
- Entity - Entity
- Data Store - Data Store
- Data store - entity
- Avoid black holes
- data flow produces nothing
- Data that is discarded represented by data flow to nowhere
17
Q
What is a Level 0 DFD?
A
- also known as a context diagram
- shows entities and flow of information to and from the information system only
18
Q
What is a Level 1 DFD?
A
- Shows entities, data stores and flow of information within the high level processes of the information system
19
Q
When is a Level (n) DFD used?
A
- When a level 1 DFD is too complex and contains too many processes, create a whole new DFD for each process that describes how the process is accomplished
- Process is called DFD Levelling
