Database distribution Database design
48 U929-J-Z125-9-76
Reasons for distributing databases among several computers within a network:
– Adaptability
Work processes can be optimized for the local computer center, and data storage can
be adapted even better to the organization of the company.
– Availability
When distributed databases are used, the data resource s are more easily available
since especially important and frequently used data can be stored in more than one
system, and the copies coupled together. If the backups are stored at different locations
and one of the systems fails, the data can still be accessed in othe r systems.
– Reduced cost
Costs are cut when fewer data stations require a continuous link to the cen tral computer
center. Most of the data required can be accessed locally; only occasionally is it
necessary to access remote data.
Figure 8: Accessing databases in another configuration within the same host
AP1 APn
...
DB1 DBn
...
Configuration 1
DBH UDS-D
AP1 APn
...
DB1 DBn
...
Configuration 2
UDS-D DBH
Host 1