Waterfall methodology is a linear-sequential life cycle model was used before. This model contains stages like * system and software requirements: * analysis: resulting in models, schema, and business rules * design: resulting in the software architecture * coding: the development, proving, and integration of software * testing: the systematic discovery and debugging of defects * the installation, migration, support, and maintenance of complete systems. Every next stage starts only prev stage was complete. Cons of such model is long time to market and risk to get result out ot client expectation. So now adays most used is agile methodology with small sprint (iterations) and goal to get fast as it possible workable solution