Distributed Database Management Systems: Lecture 3

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;...

Distributed database  Management Systems Lecture 03 Virtual University of Pakistan Resembling Setups Virtual University of Pakistan 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 Virtual University of Pakistan Resembling Setups Multiprocessor System: multiple   processors that share some form of  memory Processor Processor Processor Unit Unit Unit Memory Shared Everything Tight Coupling Virtual University of Pakistan I/O System Resembling Setups Computer System Computer System Computer System CPU CPU CPU Memory Memory Memory Shared Everything Loose Coupling Virtual University of Pakistan Shared Secondary Memory Resembling Setups Computer System Computer System Computer System CPU CPU CPU Memory Memory Memory Switch Shared Nothing Virtual University of Pakistan Resembling Setups DDBS is also different from a  centralized system having C/S  system involving network Virtual University of Pakistan Reasons for DDBS Virtual University of Pakistan Local units want control over data Consolidate data for integrated  decisions Reduce telecommunication costs Reduce the risk of  telecommunication  failures Virtual University of Pakistan Global User Local User Global User Distributed DBMS Global  Schema Node 1 Node n DBMS 1 DBMS 1 • • • • DBMS n Local User Virtual University of Pakistan 10 Promises of DDBSs Virtual University of Pakistan Transparency User View Virtual University of Pakistan System View 12 Data Independence Two types, Logical Data  Independence and Physical Data  Independence A transparent system hides the  implementation details from its  users Virtual University of Pakistan 13 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  Virtual University of Pakistan 14 Thanks Virtual University of Pakistan ... implementation details from its  users Virtual University of Pakistan 13 Network Transparency User should not only be free from  network? ?management? ?activities rather  it should be unaware of even  existence of the network... Reduce the risk of  telecommunication  failures Virtual University of Pakistan Global User Local User Global User Distributed? ?DBMS Global  Schema Node 1 Node n DBMS 1 DBMS 1 • • • • DBMS n Local User Virtual University of Pakistan...Resembling Setups Virtual University of Pakistan ? ?Distributed? ?Files: A collection of files  stored on different computers of a  network; not a DDBS