2.3 The conceptual model in the context of the wider system
The broad real-world context in which the software under development is to operate is known as the business area. This encompasses all the entities and processes, systems and subsystems that contribute to the activities of a business or other organisation, as well as the communication between them. For example, the Hospital System could be viewed as one subsystem in the general business area which covers everything that goes on in hospitals: the dispensing of medicines, the training of nurses and doctors, and so on. Each of these activities may constitute a subsystem, which may or may not be computerised, but which will need to communicate with other subsystems in the broader area.
The system domain is the particular sub-part of a business area for which a software system is being developed. The entities in the system domain are those of potential significance for that system. For example, you know from the requirements document that the entities which form part of the system domain for the Hospital System include doctors, patients and wards, but not nurses and medicines.
Finally, that part of the software that is separate from the user interface and that contains objects corresponding to those in the system domain is referred to as the core system.
In the real world, a system which dealt with the admission and treatment of patients might need to communicate with systems such as those controlling nursing shifts and the stock control of medicines. This course will not be concerned with communication between separate systems; it will consider only the communication between the system and its human users – the staff who will be interacting with the system.
Self-assessment question 1
A computer system is required for booking badminton and squash courts in a sports centre which provides a number of other facilities for its members.
(a) Of what general business area might this system domain be a part?
(b) Suggest another system domain from the same business area for which a separate computer system might be needed.
There is no single correct answer to these questions, and your solutions may be different from ours but equally valid.
(a) The system domain could be seen as belonging to the general business area of sports-centre management or administration; alternatively you could have seen it as belonging to a broader business area such as administration of leisure facilities.
(b) Taking the business area of sports-centre administration, other required systems might include things such as a membership database, a staff records system or a facilities maintenance system.
In this section you have learnt about what is involved in the process of creating a conceptual model and how this model forms the initial structural model for the eventual software system. You also learnt about the conceptual model in the context of the wider system.