The use case represents the series of interactions between actor and system. The use case document is prepared by a business analyst to provide the required details to the IT team. The various terminologies used in use cases are listed in this article.
This is the person or the system customer who will access the system to achieve some goal. Let’s say customers will access a bank ATM system for cash withdrawal.
Bank itself will act as an actor which would use an ATM system that will deposit sufficient cash in order to distribute to its valued customers and bank here will be a system.
2. Primary actor:
This is known as the actor who is the person or the system for whom the use case is built and exist which will satisfy the goal.
Let’s consider account holders in banks are primary or main actors on the scene whose main objective or goal is to either deposit cash or withdraw money from their respective accounts.
These are the set of activities that has to be performed under some prevailing conditions in order to achieve the goal.
Suppose the instance or the scenario at bank ATM which includes:
Distribution of the cash or customer login that is PIN.
Maintaining or keeping tracklog on record of the interaction which is made between customer and ATM system.4. Main success:
These are the successful interactions that will be presented or noticed. There are no failures and has steps of action in the scenario which are to be performed successfully.
Let’s say the main success scenario at the bank ATM which includes:
The requisite amount of money withdrawal by a legitimate customer and updating of the bank records which will reflect timely changes of bank transactions.
5. Extension scenario:
These are the interactions that have to be noticed only when some steps actions are not performed in the main success scenario.
Extension scenarios will be referred to as exceptional scenarios.
Let’s say an extension scenario at bank ATM will be:
ATM system which will display- will not have enough cash message or the shortage of money to be fulfilled to the customer requirements.
Developing use case:
The use case will be developed in a step-by-step manner which leads to the step-wise refinement and adding more information for each of the incremental steps.
For developing use cases- simple technical writings with the English grammar will be followed:
The goal is to specify interactions clearly who is doing? Which step is to perform?
Indeed use cases will be formulated at four levels which are been listed:
1. Actors and goals
2. Main success scenario
3. Failure conditions
4. Failure handling
Use case formulation requires main success scenarios followed by failure conditions and failure handling as well.
Other approaches for the requirement analysis:
Following methods and approaches will be employed in problem analysis;
1. State and projection concepts
2. Data flow diagrams
3. Entity relationship diagrams
State VS projection: This will suggest that the system will be operating at some specified condition which is given may be existent in one of the several states of its operation so the detailed problem analysis will be exercised for every existing state.
This kind of state-based requirement analysis will be followed while developing the process control software or the real-time software system. In the case of the projection-based approach, the system will be defined with respect to the multiple points of view which are different projections or viewpoints of the given system which are considered for the problem analysis. Its proposed software system to be developed will be analyzed by collecting various projections of the system as it provides a different perspective for the detailed analysis of the problem.
Data flow diagrams
Data flow diagrams will be referred to as data flow graphs or bubble charts. Data flow diagrams will depute the flow of data through a sequence of processing steps or transformations in the system.
DFD will be commonly used in the problem analysis and to document the software design as well.