There is a problem to be solved. (Problem - Solution)The approach from problem to solution is as follows;
Analysis: Business analyst analyzes the problem statement (and the needs) in real world with client. The output is a model of solution, for example in form of a use case.
Design: This step is nothing but in Abstract world: Designer makes the appropriate software design, which is supplied by the analyst. Design provides "what to do" for software development ("how to do" is let to software development).
Implementation: Software development team develops the application.
Software development process is an iterative process (QA, Change management, etc. see on Wikipedia)
The development process for a simple database example
(From book: Beginning Database Design, Churcher C., APress, ISBN: 978-1-59059-769-9)
