Distributed Database
DISTRIBUTED DATABASE MANAGEMENT SYSTEM
A distributed Database Management System (DDBMS) is a database in which storage devices are not all attached to a common processing unit such as the CPU. It may be stored in multiple computers, located in the same physical location; or may be dispersed over a network of interconnected computers. Unlike parallel systems, in which the processors are tightly coupled and constitute a single database system, a distributed database system consists of loosely coupled sites that share no physical components. Collections of data (e.g. in a database) can be distributed across multiple physical locations. A distributed database can reside on network servers on the Internet, on corporate intranets or extranets, or on other company networks. The replication and distribution of databases improves database performance at end-user worksites.
It allows a user to access and manipulate data from several databases that are physically distributed to several sites. A DDBMS differs from a Database Management System (DBMS) because it is responsible for providing transparent and simultaneous access to several databases that are located on dissimilar computer systems whereas a DBMS manages a single site database. This DDBMS would allow an end-user too:
1. Create and store a new part anywhere in the network.
2. Access a part without knowing where the part is physically located.
3. Delete a part from one of the databases without having to worry about the duplicated parts in other databases.
4. Update a part description in one database without having to worry about how and when all the duplicated parts will be updated in other databases.
5. Access a part from an alternative computer when, say, the nearest computer is not available.
To ensure that the distributive databases are up to date and current, there are two processes: Replication and Duplication.
• Replication involves using specialized software that looks for changes in the distributive
A distributed Database Management System (DDBMS) is a database in which storage devices are not all attached to a common processing unit such as the CPU. It may be stored in multiple computers, located in the same physical location; or may be dispersed over a network of interconnected computers. Unlike parallel systems, in which the processors are tightly coupled and constitute a single database system, a distributed database system consists of loosely coupled sites that share no physical components. Collections of data (e.g. in a database) can be distributed across multiple physical locations. A distributed database can reside on network servers on the Internet, on corporate intranets or extranets, or on other company networks. The replication and distribution of databases improves database performance at end-user worksites.
It allows a user to access and manipulate data from several databases that are physically distributed to several sites. A DDBMS differs from a Database Management System (DBMS) because it is responsible for providing transparent and simultaneous access to several databases that are located on dissimilar computer systems whereas a DBMS manages a single site database. This DDBMS would allow an end-user too:
1. Create and store a new part anywhere in the network.
2. Access a part without knowing where the part is physically located.
3. Delete a part from one of the databases without having to worry about the duplicated parts in other databases.
4. Update a part description in one database without having to worry about how and when all the duplicated parts will be updated in other databases.
5. Access a part from an alternative computer when, say, the nearest computer is not available.
To ensure that the distributive databases are up to date and current, there are two processes: Replication and Duplication.
• Replication involves using specialized software that looks for changes in the distributive