Database Reference
In-Depth Information
Figure 22-1.
Benefits of Distributed Database Systems
When weighed against the challenges posed by distributed database (discussed
later), they outweigh them by a huge margin; we therefore expect the continued
proliferation of distributed databases.
22.3 Twelve Rules for Distributed
Database Systems
In his classic text,
Introduction to Database Systems
, Christopher Date discusses twelve
rules (objectives) for distributed database systems [Date, 2004]. Let us take a brief look at
these rules.
Rule 1: Local Autonomy
The sites should be autonomous to the maximum possible extent. All operations at a site
are governed by that site alone. This is not always entirely possible, but is an objective to
strive for.
Rule 2: No Reliance on Central Site
This is a consequence of objective 1. The sites must be treated as equals. There is no
reliance on a central site. Reliance on a central site would make the system vulnerable
to the central site (bottleneck could occur or the central site could go down). This is
undesirable.
