Thanks a lot for your reply Ted,
I have achieve the above requirements using :
1) custom code
2) Sync Tool (SQL to Sharepoint list)
3) Event Receiver (For deleting records from list as well as database)
4) Webservices for updating data into sharepoint list.
5) Sharepoint object model (Deleting records from Sharepoint list while Sync SQL to SP list)
By the way it takes a lot of efforts and coding too..:)