There are several different approaches to software development, much like the various views of political parties toward governing a country. Some take a more structured, engineering-based approach to developing business solutions, whereas others may take a more incremental approach, where software evolves as it is developed piece-by-piece. Most methodologies share some combination of the following stages of software development
These stages are often referred to collectively as the software development lifecycle, or SDLC. Different approaches to software development may carry out these stages in different orders, or devote more or less time to different stages. The level of detail of the documentation produced at each stage of software development may also vary.
These stages may also be carried out in turn (a “waterfall” based approach), or they may be repeated over various cycles or iterations (a more "extreme" approach). The more extreme approach usually involves less time spent on planning and documentation, and more time spent on coding and development of automated tests. More “extreme” approaches also promote continuous testing throughout the development lifecycle, as well as having a working (or bug-free) product at all times.
More structured or “waterfall” based approaches attempt to assess the majority of risks and develop a detailed plan for the software before implementation (coding) begins, and avoid significant design changes and re-coding in later stages of the software development lifecycle planning.
Consistency in Software
In order to ensure that software can evolve in a way that maintains its inherent multidimensionality, one must ensure that the different dimensions evolve together in a consistent manner. Software has too many dimensions to combine within a single framework. A good mechanism should not be geared to a specific problem such as ensuring the consistency of a UML class diagram with the source code. Instead it should be flexible enough to handle the broad range of dimensions that are actually involved in software development.