A data manipulation language (DML) is a family of computer languages including commands permitting users to manipulate data in a database. This manipulation involves inserting data into database tables, retrieving existing data, deleting data from existing tables and modifying existing data. DML is mostly incorporated in SQL databases.
The waterfall model is a sequential software development process model that follows the following defined phases:
Using the software development life cycle's (SDLC) common steps, the waterfall model enforces moving to the next phase only after completion of the previous phase. Returning to a previous phase is frowned upon unless there is a clear need to do so.
As its name implies, the phases in the waterfall model consistently progress downward. These phases should be followed in sequence to be effective, and in some industries - such as construction and manufacturing - the process must be followed.
In theory, the waterfall model sounds like a good practice, but it has been criticized by many in the software development industry. First, an SDLC phase cannot be perfected before moving to the following phase. Also, in its literal form this model lacks flexibility for requirement and design adjustments, which makes it highly difficult for programmers and developers to integrate design adjustments.
However, there are some sound principles from the waterfall model that can be applied to successful software development. This is a partial list of these principles:
The waterfall model was an early attempt to provide structure, metrics and control to the development of large and complex application systems, usually mainframe systems.
Read More »
Join 138,000+ IT pros on our weekly newsletter
Home | Advertising Info | Write for Us | About | Contact Us
2010 - 2015
Partner Sites :