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Distributed database Management Systems. Lecture 03. Resembling Setups. Distributed Files: A collection of files stored on different computers of a network; not a DDBS DDBS is logically related, common structure among files, and accessed via same interface. Processor Unit. Processor Unit.
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Distributed database Management Systems Lecture 03
Distributed Files: A collection of files stored on different computers of a network; not a DDBS • DDBS is logically related, common structure among files, and accessed via same interface
Processor Unit Processor Unit Processor Unit Memory Shared Everything Tight Coupling I/O System Resembling Setups • Multiprocessor System: multiple processors that share some form of memory
Computer System Computer System Computer System CPU CPU CPU Memory Memory Memory Shared Secondary Memory Shared Everything Loose Coupling Resembling Setups
Computer System Computer System Computer System CPU CPU CPU Memory Memory Memory Switch Shared Nothing Resembling Setups
Resembling Setups • DDBS is also different from a centralized system having C/S system involving network
Local units want control over data. • Consolidate data for integrated decisions • Reduce telecommunication costs. • Reduce the risk of telecommunication failures.
Global User Global User Local User Distributed DBMS Global Schema Node 1 Node n • • • • DBMS 1 DBMS n DBMS 1 Local User
User View System View Transparency
Data Independence • Two types, Logical Data Independence and Physical Data Independence • A transparent system hides the implementation details from its users
Network Transparency • User should not only be free from network management activities rather it should be unaware of even existence of the network • Location Transparency and Naming Transparency