Review Questions Model-driven development techniques emphasize the drawing of models to help visualize and analyse problems, define business requirements, and design information systems. They could include: –Modern structured design –Information engineering –Object-oriented –Prototyping Joint application development (JAD) is a technique that complements other systems analysis and design techniques by emphasizing participative development among system owners, users, designers, and builders. Rapid application development (RAD) is the merger of various structured techniques with prototyping techniques and joint application development techniques to accelerate systems development. Briefly describe the 3 most common system design approaches or strategies?

Review Questions How can a successful and thorough systems analysis be ruined by a poor systems design? If the design is poorly done, the construction and implementation phases will be significantly slowed down. The programmers will find themselves constantly clarifying erroneous or incomplete design specifications. Users may find that the delivered system doesn't fulfill the requirements that were agreed upon during systems analysis. The lifetime costs of the system will be exceeded since considerable maintenance costs will likely be incurred to correct the design deficiencies.

Review Questions A field is the implementation of a data attribute. Fields are the smallest unit of meaningful data to be stored in a file or database. A record is a collection of fields arranged in a predefined format. A file is the set of all occurrences of a given record structure. Define the terms Field, Record and File.

Review Questions Primary keys are fields whose values identify one and only one record in a file or database. Foreign keys are pointers to the related records in a different file in a database. Foreign keys serve as the link between different types of records in a database. Differentiate between Primary and Foreign Keys. What important role do Primary key serves?

Review Questions Describe Data Normalisation and its purpose. Normalisation is the process of simplifying the relationship between data elements in a record. The purpose of normalisation is to produce a stable set of relations. To achieve a design that is highly flexible. To increase the quality of database design.

Data Normalisation Example First Normal Form –1NF is where a table has no fields that can have more than one value for a single instance of the entity. Any fields that can have multiple values actually describe a separate entity. –Example – Member Order (adapted from text p.290) Order No Order DateMember Name Product Number Product DescriptionQuantity Ordered /05/2003Sony31155Red Pen Photocopy Paper /05/2003Vodafone55123HP Printer Cartridge Photocopy Paper50

Data Normalisation Example – part 2 Order No Product Number Product DescriptionQuantity Ordered Red Pen Photocopy Paper HP Printer Cartridge Photocopy Paper50 Order No Order DateMember Name /05/2003Sony /05/2003Vodafone Tables now in 1NF Member Order Order Details

Review Questions To what extent should system users be involved in output design? How would you get system users involved? End-users are the recipient of all outputs. Therefore, end-users need to actively participate in output design. End-users can be involved in a number of ways. They should be asked to identify contents and describe how the outputs will be used. They could be asked to sketch first drafts of reports. After analysts study those drafts and prepare alternative sketches, the end-users should review the possible designs and accept responsibility for approving the "best" design.

Review Questions What implications would input design likely have on output design? Inputs ultimately determine outputs. Therefore, it becomes important to validate that the inputs are sufficient to produce the outputs

Review Questions Why do we spend time on User Interface Design? - Firstly, and most importantly, to take into account human engineering issues so as to make the system user friendly, and easy to use and understand. - To understand the users and their tasks. - To allow the user to be involved in the Interface Design. -To test the system on actual users.