Visual Basic

What Is Design?

Design is the process of taking a business requirement and applying the constraints of technology, finance, and time. It is a compromise between the needs of a business and the limitations of the computer. It is a mixture of art and science; it is engineering. Design requires its participants to be masters of business and technology in order to draw the appropriate compromise. Designers need to be communicators and influencers. They need to be leaders.

Designers must possess current business and technical knowledge. The introduction of Visual Basic 6 demands that designers work to understand the new technical environment. A design is a specification for building an application. It applies architectural principle to a specific system. The strategy for implementation must be determined as part of the design. The system must function within the technical infrastructure of a business.

A logical model specifies what is required. For the model to be implemented, it must be tempered with reality. The design model has to be accurate to be implemented. The design model might be very different from the logical model. Rarely can the logical model be implemented directly; unfortunately, many try to do just that. For example, it is well known that a third normal form database design often performs poorly, but it's often tried because a logical database design doesn't take performance into account. A design model has to include all the data, not just the data that was thought of. It has to include all the processing, including the housekeeping and the audit trails. It has to account for peculiarities in database query optimization. It should consider the skills of the team, the build strategy, configuration management, and a host of other things that the analyst who creates the logical model can safely ignore.

Logical modeling should occur at the start of the design-and a long way from the end. Design requires detailed technical knowledge of the implementation environment. That environment includes not just technology but people too. The conversion of a logical data model to a robust and efficient physical design is a complex process that must be performed by the system designer in conjunction with the technical specialists. Only together can they make the appropriate compromises between business needs and technical constraints. The system designer from the application development team is unlikely to have the technical knowledge to make best use of the technology. The technical specialist is unlikely to understand where the business can compromise and where it cannot (or will not).

The process of design starts during the feasibility stage and continues throughout the life of a Visual Basic 6 distributed development project. Design does not follow analysis; it is more likely to precede it. Design is then a process of gradual refinement from high-level strategies to detailed specification that is continually influenced by and influences analysis. Requirements are generally unstable. They might be specified differently by different people. The software crisis is not in requirements gathering and specification, but in design. Designs must be able to cope with change and uncertainty. A successful system will change, but only a well-architected system will cope effectively with this change and at low cost. The focus of a project must be on design.