Why is ssadm used

This stage is especially important as any omissions will have a bad effect on the whole project. Formulation of business systems requirements. Evaluation of the implication and benefit of each proposed option. Identification of functional and non-functional require- ments in detail.

Proposal of new methods and techniques in order to describe processing and data structures. Stage 4: Technical systems options: Definition and selection Maintenance of specific technical options, such as different methods of implementation. Stage 5: Logical design: May be simultaneously to stage 4. User dialogues, update processes, enquiry processes are defined and selected. Stage 6: Physical design: After producing a physical design, creating a function and data design, the SSADM cycle is completed and the applications are ready for delivery.

There is mainly one method that focuses especially on fast, flexible and low resources development of IS. IT uses prototyping to involve users, so this definitely meets their requirements, and can help to develop IS faster.

Its major principles are as follows:. The parts of organisational culture, on which SSADM, if applied, has an effect, are control, direction, risk tolerance, and communication patterns. So, an organisation with a structured and hierarchical culture, for example role or person culture, will have less problems adopting SSADM and getting its employees accustomed to it. Whereas organisations with power or task cultures, which allow the single employee to take more responsibility, and which in general tend to be less bureaucratic and more dynamic, will have difficulties alongside the Structured Systems Analysis and Design Methodology.

And these are closely related to the stability of the business situation of the organisation. It can only profit from the advantages that SSADM provides, such as better quality due to the review of each stage or meeting the requirements more exactly due to emphasis on the requirements analysis stage , when the following criteria are met:. First of all the volume and the time that is at disposal must be large enough to undergo the whole development process.

Secondly, the short term business situation is not supposed to change drastically, because SSADM does not intend to change the specifications that were made in advance after the review of the stage had been completed. This fact can lead to the problem that the end result deliver does not meet the business requirements at the point of time when it is delivered.

Considering the long-term situation, SSADM has shown that it increases the overall quality of Information Systems within an organisation. The fact that SSADM has become the imperative development methodology for government departments and their suppliers of IS proves this fact. However, it must be considered that SSADM was developed especially for these kinds of companies and that government projects, in general, have enough time, money and human resources to cope with the bureaucratic nature of SSADM.

It is said to be very bureaucratic, time and cost consuming. Only for large organisations, such as government departments does it make sense to adopt this structured methodology. For medium-sized companies, developing a comparatively small information system, there are better solutions for developing an IS. Some discussion has been made about it in 3. But bearing in mind the limited resources of a medium-sized company, it should also consider using an off-the-shelf product, which is much less expensive and timeconsuming and has already been tested by various other companies.

Bocij, P. Hutchings, T. Krallmann, H. Robbins, S. P Organizational Behaviour: concepts, controversies and applications. Logical data modeling determines the entities -- and the relationships between them -- in the system. Data flow modeling determines the ways in which data changes from one form to another, the holding areas for the data, the entities that send data into the system and the routes through which the data flows. Entity event modeling documents how events within the business affect the entities of the information system.

When these three methodologies and viewpoints are provided, the model is more accurate and complete. Such a deep and through analysis of a system greatly reduces the chance of any information being misunderstood at the beginning stages of the project.

One of the main features of SSADM is the intensive user involvement in the requirements analysis stage. The users are made to sign off each stage as they are completed assuring that requirements are met. The users are provided with clear, easily understandable documentation consisting of various diagrammatic representations of the system. SSADM breaks up a development project into stages, modules, steps and tasks. It is a part of requirements gathering and consists of well defined stages, steps and products.

The techniques used in SSADM are logical data modeling, data flow modeling and entity behavior modeling. Logical Data Modeling: This involves the process of identifying, modeling and documenting data as a part of system requirements gathering.

The data are classified further into entities and relationships. Data Flow Modeling: This involves tracking the data flow in an information system. The following activities are part of this stage: Prepare for physical design. Complete the specification of functions. Incrementally and repeatedly develop the data and process designs. Techniques The 3 most important techniques that are used in SSADM are: Logical Data Modeling This is the process of identifying, modelling and documenting the data requirements of the system being designed.

The data are separated into entities things about which a business needs to record information and relationships the associations between the entities. Data Flow Modeling This is the process of identifying, modelling and documenting how data moves around an information system. Data Flow Modeling examines processes activities that transform data from one form to another , data stores the holding areas for data , external entities what sends data into a system or receives data from a system , and data flows routes by which data can flow.

Entity Behaviour Modeling This is the process of identifying, modelling and documenting the events that affect each entity and the sequence in which these events occur. Technical System Specification Stage.

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