Hayatx

boilermakerwrapperElectronics - Devices

Nov 8, 2013 (4 years and 1 month ago)

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Hayat Abu
-
Ghazaleh

1.

Centralised database:

a database at a single physical location, usually employed in
conjunction with centralized data processing.

2.

Distributed database:
a database maintained in physically separated locations and
supported by a computer network in order to make it possible to access the database from
various points in the network.




Very complex



Not economical



Difficult to maintain integrity



Inexperience



L
ack of standards



Database design more complex



Additional software not required



Operating system should support distributed environment


3.

DDBMS:
Distributed Database Management System. A centralized application that manages
distributed databases as if it wer
e stored on one computer. It synchronizes all the data
periodically, and when multiple users are accessing the database and making changes, it
prevents data from being deleted and overwritten.

4.

Any computer type may be used. Different DBMS may be used to
manage each fragment of
the database.

5.





6.

VPN:

V
irtual
P
rivate
N
etwork.
Decentralised, distributed require VPN.

Centralised

Decentralised

Distributed

Server

Mainframe Computer

LAN


Server

Mainframe Computer

Computers

WAN

Mainframe Computer

Computers

WAN

Server