Decision Support System

Im going to open new pharmacy and I would like to develop a program helps in disease diagnosis the system will contain the following - patient database containing ( name , address , telephone no, etc ) -Data base for all drugs (names, usage , side effect) -The system will ask the patient about his symptoms then it will decide weather the symptoms resulted from therapy side effect or another disease Also the system will provide the suitable prescription or medical advise i would like to know the expecting price and demo thanks