Database management

A  Central Client management database  to manage clients contacts , Clients co information , filing date line for Public accounting firm  Or CPA having 300- 700 corporate & individuals many of which are inter related . It must include :
- A. Details of Clients like contact  & details of person , file numbers ,tax ref ,  Co # , type of work  Etc
B..

- Can be share & access by different Depts on a local network . On crowd Version is optional at this stage
-C.easily updated & call up  info through a simple  One page inter face page
-D..This Database  can  be & is a basis for adding  more modules link to  other  Dept of acc , audit , tax & sec  database that  monitor  different filing date line  , work progress & completion date , person in charge etc
E..Info in database can be sort or extract in different reports base on needs
-F..  Must be flexible to allow adding of more fields  or data  as need arises in future