Saturday, 14 March 2015

Date's Twelve Rules for Distributed Database Systems - Local Autonomy


Date's Twelve Rules for Distributed Database Systems - Local Autonomy



1. Local autonomy
  • All operations at a given site are controlled by that site. With local autonomy, each site has the capability to control local data, administer security, and log transactions and recover when local failures occur and to provide full access to local data to local users when any central or coordinating site cannot operate. Data at local sites are owned by that site itself.
  • Local operations remain purely local.
For example, in the figure given below, the database consists of all data stored at Chennai, Mumbai, and New Delhi sites. Actually, the data are distributed and stored at different locations. As we know, database transactions can be handled by Transaction manager component. For the case given below, in a distributed database, the Transaction manager of Chennai site is the owner of data stored at Chennai site, the transaction manager of Mumbai site is the owner of data stored at Mumbai site, and so on.

Distributed database with servers at different locations







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