Distributed Database Management Systems: Lecture 3. The main topics covered in this chapter include: local units want control over data; consolidate data for integrated decisions; reduce telecommunication costs; reduce the risk of telecommunication failures;...
Trang 1Distributed database Management Systems
Lecture 03
Trang 2Resembling Setups
Trang 3Distributed 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
Trang 4Multiprocessor System: multiple
processors that share some form of
Unit
Processor
Unit
Processor
Unit
Memory
I/O System
Shared Everything
Tight Coupling
Trang 5CPU
Memory
Computer System
CPU
Memory
Computer System
CPU
Memory
Computer System
Shared Secondary Memory
Shared Everything
Loose Coupling
Trang 6CPU
Memory
Computer
System
CPU
Memory
Computer System
CPU
Memory
Computer System
Switch
Shared Nothing
Trang 7DDBS is also different from a centralized system having C/S system involving network
Trang 8Reasons for DDBS
Trang 9Consolidate data for integrated
decisions
Reduce telecommunication costs
Reduce the risk of
telecommunication failures
Trang 10DBMS 1DBMS 1 • • • • DBMS n
Global User Global User
Global Schema Local User
Trang 11Promises of DDBSs
Trang 12Transparency
Trang 13Two types, Logical Data
Independence and Physical Data Independence
A transparent system hides the implementation details from its users
Trang 14User 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
Trang 15Thanks