Describe centralized and client/ server architecture of DBMS?

Centralized database system: The centralized database system consist of a single processor together with it associated data storage devices and other peripherals. It is physically confined to a single location. The data can be accessed from the multiple sites with the use of a computer network while the database is maintained at the central site.

Disadvantages of centralized database system::

• When the central site computer or database system goes down, then everyone is blocked from using the system until the system comes back.
• Communication costs from the terminals to the central site can be expensive.
  
  
  

Client server dbms:- Client / server architecture of database systems has two logical components namely client and server. Client is generally personal computer or workstations whereas server is large workstations, mini range computer system or a mainframe computer system. The application and toals of DBMS run on one or more client platforms, while the DBMS softwares reside on the server. The server computer is called front end. These server and client computer are connected into a network. The application and tools act as client of the DBMS making requests for its services; client/ server architecture handles the graphical user interface (GUI) and does computations and other programming of interest to the end user.

ADVANTAGES:

1. CLIENT / SERVER system has less expensive platforms to support applications that had previously been running only on large and expensive mini or main frame computers.
2. Client/ server environment facilities in more productive work by the users and making better use of existing data.
3. It is more flexible as compared to the centralized systems.
4. Responsive time 7 throughput is high.
5. A single dg(on server) can be shared across several distinct client (application) system.

DISADVANTAGE:

1. Programming cost is high in client / server environment, particularly in initial phases.
2. There’s a lack of management tools for diagnosis, performance monitoring and tuning and security control, for the DBMS client and OS and networking environments.