Date's Twelve Rules for Distributed Database Systems - Location independence

Date's Twelve Rules for Distributed Database Systems - Location independence

4. Location independence (Location Transparency)

The end users and even application programmers need not know where the data are physically stored. Location independence objective insists the hiding of location detail of the data from the end users. This provides the security to the data. Also, this should give a feeling to the users that all data were stored at a local central site.

For example, consider the figures given below;

According to figure 1, the data are available at Chennai, Mumbai, and New Delhi (different locations). User A, who is near to Mumbai site, is trying to access data. Assume that the requested data is available at Chennai site. For user A, the data access should give a feel like the figure 2. That is, the data available centrally at user’s location (say, Mumbai site, in our case). Observe the difference between two images.

Figure 1 - Actual request of user A reaches Mumbai site

Figure 2 - For User A, the site details are hidden. User does not aware of multiple sites.