Distributed Database - Advantages

Advantages

• Management of distributed data with different levels of transparency like network transparency, fragmentation transparency, replication transparency, etc.
• Increase reliability and availability.
• Easier expansion.
• Reflects organizational structure — database fragments are located in the departments they relate to.
• Local autonomy or site autonomy — a department can control the data about them (as they are the ones familiar with it.)
• Protection of valuable data — if there were ever a catastrophic event such as a fire, all of the data would not be in one place, but distributed in multiple locations.
• Improved performance — data is located near the site of greatest demand, and the database systems themselves are parallelized, allowing load on the databases to be balanced among servers. (A high load on one module of the database won't affect other modules of the database in a distributed database.)
• Economics — it costs less to create a network of smaller computers with the power of a single large computer.
• Modularity — systems can be modified, added and removed from the distributed database without affecting other modules (systems).
• Reliable transactions - Due to replication of database.
• Hardware, Operating System, Network, Fragmentation, DBMS, Replication and Location Independence.
• Continuous operation.
• Distributed Query processing.
• Distributed Transaction management.

Single site failure does not affect performance of system. All transactions follow A.C.I.D. property: A-atomicity, the transaction takes place as a whole or not at all; C-consistency, maps one consistent DB state to another; I-isolation, each transaction sees a consistent DB; D-durability, the results of a transaction must survive system failures. The Merge Replication Method is popularly used to consolidate the data between databases.