Unit 3 - From domain modelling to requirements Flashcards
What is the function of business rules?
They constrain how a business is run
From a typical business description, what should we be able to identify?
Business processes in the domain and business rules (constraints)
Verification is?
The set of activities that ensure that a solution is being
correctly developed, i.e. that it is taking into account the business rules.
Validation ensures?
That what is being built satisfies the business, i.e. that
the business rules implemented are the ones that the business wants
What are the important properties that a representation of business rules should have?
The important properties are as follows:
◦ Business rules that apply to the whole business should be represented separately from project specific models.
◦ They should be easy to verify (possibly automatically) and validate.
◦ They should be represented in a readable language that is easy to verify.
Business processes define?
What is done in a business, by whom, in what
order, needing which resources, and with what consequences
How do you represent business processes?
With UML activity diagrams.
An activity diagram shows a process as a set of activities and describes how they must be coordinated – which ones depend on others having been completed first and where activities can be carried out in parallel
For a process of making a hot drink, we need to boil water in a kettle. What are the two steps involved in this task?
- Fill Kettle
2. Boil Water
What are the basic elements of an activity diagram?
Activities and Transitions.
Activities are shown as rounded boxes and Transitions are shown as lines with arrows.
There are two predefined activities, start and stop, which are represented as filled circles
UML decision nodes allow what?
To represent alternative mutually exclusive, ways out of an activity. A decision node is drawn as a diamond.
The flow out of decision nodes are constrained with Boolean tests, known as?
The Boolean tests are known as Guards, written inside square brackets.
Each of the transitions leaving the first decision diamond has a guard to determine which path should be taken under a given condition
A diamond shape in an Activity diagram can also be used as a?
Merge node, which brings together alternative mutually exclusive flows.
A merge node will be reached only by one of the alternative flows and has a single outgoing flow.
What causes a transition in an activity diagram?
A transition in an activity diagram is caused by the completion of an activity
What is a synchronisation bar, and when is one used in an activity diagram?
A synchronisation bar is used to mark the point when two or more activities can take place concurrently (a fork) or when a number of concurrent tasks must finish before continuing to the next activity (a join).
An activity diagram can be used to represent what?
The workflow of an existing process.
It represents the sequence of activities and helps identify the stages at which each role requires some interaction with the process.
This is of particular benefit when we want to investigate the steps that people – and any existing systems – take in order to do their jobs.
When modelling a workflow that involves more than one role, it is possible to identify which role is responsible for a particular activity. To do this in UML, we partition an activity diagram into swimlanes – one swimlane for each role
How does the partitioning of activities into swimlanes help us understand a set of activities?
Swimlanes group activities associated with different roles. The swimlanes show the role that is responsible for each activity.