Advantages of homogeneous distributed database system
Answers
Answer:Homogeneous Database:-
In a homogeneous distributed database, all the sites use identical DBMS and operating systems. Its properties are −
• The sites use very similar software.
• The sites use identical DBMS or DBMS from the same vendor.
• Each site is aware of all other sites and cooperates with other sites to process user requests.
• The database is accessed through a single interface as if it is a single database.
There are two types of homogeneous distributed database −
• Autonomous:- Each database is independent that functions on its own. They are integrated by a controlling application and use message passing to share data updates.
• Non- Autonomous:- Data is distributed across the homogeneous nodes and a central or master DBMS co-ordinates data updates across the site.
Heterogeneous Database
In a heterogeneous distributed database, different sites have different operating systems, DBMS products and data models.
Its properties are −
• Different sites use dissimilar schemas and software.
• The system may be composed of a variety of DBMSs like relational, network, hierarchical or object oriented.
• Query processing is complex due to dissimilar schemas.
• Transaction processing is complex due to dissimilar software.
• A site may not be aware of other sites and so there is limited co-operation in processing user requests.
There are two types of heterogeneous distributed database −
• Federated − The heterogeneous database systems are independent in nature and integrated together so that they function as a single database system.
• Un-federated − The database systems employ a central coordinating module through which the databases are accessed.