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Systems Development Models Cheat Sheet by

Systems Development Models

Activity Diagrams

Collect inform­ation sources
Use inform­ation already collected for the constr­uction of use case diagrams
Find activities and actions
Adopt actors from business use cases
And who is respon­sible for each action. Unit or person.
Connect actions
In Which Order are Actions Processed? Which conditions have to be met in order for an action to be executed? Where are branches necessary? Which occur simult­ane­ously?
Refine activities
Do any other activity diagrams have to be added?
Verify the view
Is everything correct?

System Sequence Diagram

1. Define who will initiate the intera­ction. Draw an actor on the diagram to specify who kick starts the intera­ction within a system
2. Draw the first message to a sub-sy­stem. Specify the message sent from the actor who begins the intera­ction to the first point of contact in the system.
3. Draw message to other sub-sy­stems. Send other messages between objects (i.e. lifelines) in the system.
4. Draw return message to actor. Send return messages back to the original callers upon receiving their messages.
5. Send/R­espond to anonymous actors. Send messages to unknown receivers or receive messages from unknown senders.

Document a workflow

1. Identify the process.
2. Name your process
3. ID a clear start point and end point
4. Identify your purpose for diagra­mming the workflow.
5. List or draw out a series of steps
6. Look for exceptions or rules
7. Use the symbols

ERD Shapes

Steps to create a Domain Model Class

1.Identify candidate conceptual classes
2.Draw them in a UML domain model
3.Add associ­ations necessary to record the relati­onships that must be retained
4.Add attributes necessary for inform­ation to be preserved
5.Use existing names for things, the vocabulary of the domain

Common associ­ations

•A is subpar­t/m­ember of B. (SaleL­ine­Ite­m-Sale)
•A uses or manages B. (Cashier –Register, Pilot-­air­plane)
•A commun­icates with B. (Student -Teacher)
•A is transa­ction related to B. (Payment -Sale)
•A is next to B. (SaleL­ine­Ite­m-S­ale­Lin­eItem)
•A is owned by B. (Plane­-Ai­rline)
•A is an event related to B. (Sale-­Store)

Activity Diagram

Graphical repres­­en­t­a­tions of workflows of stepwise activities and actions with support for choice, iteration and concur­­rency. Show the overall flow of control. UML Diagram.

Activity Diagram Symbols

Class Diagrams - Top Down

Identify and model classe­s—Which classes do we need?
Identify and model associ­ati­ons—How are the classes connected?
Define attrib­ute­s—What do we want to know about the objects?

Class Diagram - Bottom Up

List required queries and inputs­—What does the IT system need to deliver and accept?
Formulate queries and inputs—How exactly should the display look?
Conduct inform­ation analys­is—­Which classes, associ­ations, and attributes do we need?
Consol­idate class diagra­ms—How does everything fit together?
Verify the class diagra­ms—Is everything correct?

ERD crows leg meanings

ERD example


Package Diagram example

Use case diagram elements

Sequence Diagram elements

Class Diagram

ER Model

ID entities (Nouns, names)
ID relati­onships (verbs, conveys an action)
ID and assosciate attributes with entities or relati­onships
Determine candidate, primary and alternate key attributes
Check ER model for redundancy and remove if found
Check ER model supports user transa­ctions
Review model with users
Create tables
Normalise structure
Check support user intera­ctions
Check Business Rules
Review with users

Monopoly Game Domain Model

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