A CASE tool is a computer-based software that supports one or multiple system development methods (Jarzabek and Huang, 1998) at different stages of system development. It is primarily introduced to help system analysts and developers to build system more consistently and efficiently. It is noted that most of the system development methodologies, including Object Oriented modeling methodology, are deeply embedded in the CASE tools (Adhikari, 1996). A survey of the CASE tool market showed that the annual world wide market for CASE tools was $4.8 billion in 1990 and grew to approximately $12.11 billion in 1995 (Jarzabek and Huang, 1998).