Three key issues we have to consider:
• Data Allocation: where are data placed? Data should be stored at site with "optimal" distribution.
• Fragmentation: relation may be divided into a number of sub-relations (called fragments) , which are stored in
different sites.
• Replication: copy of fragment may be maintained at several sites.
The database can be of two types either distributed or centralized . In distributed database the data is in different systems. In centralized database the data is in a single central system.We can categorize database as either distributed or centralized . In centralized database the data is in a single centralized system. While In distributed database the data is in different systems .
Centralized design is one of the two major methods of designing a networked database, the other being distributed design. In a centralized design, all the database table schema and the data reside in one place where all of the users access it (i.e., central to the users.) Conversely, a distributed design replicates the schema in multiple places and segments the data amongst the multiple sets of tables. Each group of users accesses a particular distributed set of tables with the data relevant to their group. This improves data security and retrieval time for the users at the cost of increased complexity of database maintenance and backup.
As we know a database is used for storing data. A database may be centralized or may be distributed. A distributed database is one in which data is distributed in different systems.
Distributed Database Consulting was created in 1997.
1 Explain architecture of Distributed Database systems? Also, explain the reasons for building distributed database systems?
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dISTRIBUTED. DATABASE. ACCESS. PRIMITIVES. In the examples of the ... usemore powerful primitives
The importance of a distributed database in that it allows for easy expansion and increased reliability . A distributed database does not contain all the information stored on one disk or attached to one CPU.
structure of distributed databases
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Wesley W. Chu has written: 'Distributed Database Systems - Distributed Systems -' 'Distributed Processing and Database Systems'
A distributed database is a database in which portions of the database are stored on multiple computers within a network. Users have access to the portion of the database at their location so that they can access the data relevant to their tasks without interfering with the work of others. A centralized distributed database management system manages the database as if it were all stored on the same computer.