I strongly advise against building your own in a hurry, especially if you plan on putting a lot of important data in it. There are plenty of open source CRM systems out there that will probably accomplish your goals. There are also paid systems that will handle everything for you, except data entry.
Building your own is going to take a lot of work, and if not done properly, you'll spend more time maintaining the code than actually using it.
Thanx for your advice.
I know that it is very time consuming and cumbersome to create a new crm project but i m not intented to create a complete crm application.
I want to learn how data warehousing and data mining are done in crm.
So i will be concentrating on that part only. Can you please tell me how it is done in a crm application?
I had gone through various crm applications available in the market but is unable to find how things are working in the backend.