Explain Iterative Methodology
The basic principle of the iterative methodology is to release bigger and bigger portions of the complete project to discover problems early and make necessary adjustments when the requirements cannot be adequately defined by users. In the waterfall methodology, you go live once, and prior to that you have a period of testing when you try to fix errors. In the iterative methodology, you release a version of the system several times into production to be used by selected users. For example, say it will take eight months to build a data warehouse system; using the waterfall methodology, it is going live in month 8. If you use the iterative methodology, you will be releasing a version in months 3, 6, and 8 (three times) into production. You build the data warehouse in pieces horizontally. In each iteration, you build a piece from end to end. In other words, in each iteration you do the requirements, design, build, test, put it into production, and have the users use it. And you build all the necessary components to support that piece in production.
Questions on Iterative/Incremental Methodology