Đang tải... (xem toàn văn)
Distributed Database Management Systems: Lecture 1. The main topics covered in this chapter include: introduction to database and distributed systems in general; architectures and design issues of DDBS; technological treatment; theoretical aspects of the topic;...
In the name of Allah Virtual University of Pakistan Distributed Database Management Systems Lecture - 01 Virtual University of Pakistan References 1Distributed Database Systems (2nd Edition) by T.M., Ozsu, P. Valdusiez 2 Distributed Database Systems. By D. Bell, J. Grimson, Addison Wesley, 1992 Virtual University of Pakistan References 3 Distributed Systems: Concepts and Design, 4th Edition, by G. Coulouris, J. Dollimore, T. Kindberg, Addison Wesley Prerequisites: Database Management Systems, Computer Networks Virtual University of Pakistan Course of Course Introduction to database and Distributed Systems in general Architectures and Design Issues of DDBS Technological Treatment Theoretical Aspects of the topic Virtual University of Pakistan Little bit of History Traditional File Processing System: the very first form of business data processing Each program contains data description that it manipulates Redundancy of data Problems in maintenance Virtual University of Pakistan Examination Registration Library Applications Examination Applications Registration Applications Library Data Files Examination Data Files Registration Data Files Library Program and Data Interdependence Virtual University of Pakistan File Processing Systems Library Exam Registration Reg_Number Reg_Number Reg_Number Name Name Name Father Name Address Father Name Books Issued Class Phone Fine Semester Address Grade Class Duplication of Data Vulnerable to Inconsistency Virtual University of Pakistan History continues Database Approach: (Also called centralized database) Database is a shared collection of logically related data Virtual University of Pakistan Database Approach PROGRAM PROGRAM PROGRAM Data Description Data Manipulation Database … Takes care of all major drawbacks of File System Environment plus more Virtual University of Pakistan 10 Distributed Computing System A number of autonomous processing elements that are connected through a computer network and that cooperate in performing their assigned tasks Virtual University of Pakistan 11 Distributed Computing Systems Distributed System Software enables computers to coordinate and share The thing being distributed? – Processing logic – Functions – Data – Control; All are relevant and important here Virtual University of Pakistan 12 Classifications of DCS Degree of Coupling – How closely systems are connected – May be the measured as ratio of messages interchanged to the local processing – Could be Weak (over the network) or Strong (if components are shared) Virtual University of Pakistan 13 Classifications of DCS Interconnection structure – Could be point to point or a common interconnection channel Interdependence of Components Synchronization Factors are not totally independent Virtual University of Pakistan 14 Why DCS? Suits some of the Organizational Structures; more reliable and responsive Nature of some applications Technological Push Virtual University of Pakistan 15 DCS’s Alerts Information Islands and Lack of Standards Difficulties in Large Application Design Too Many Options Available Virtual University of Pakistan 16 .. .Distributed Database Management Systems Lecture - 01 Virtual University of Pakistan References 1? ?Distributed? ?Database? ?Systems (2nd Edition) by T.M., Ozsu, P. Valdusiez 2? ?Distributed? ?Database? ?Systems. ... in performing their assigned tasks Virtual University of Pakistan 11 Distributed? ?Computing Systems ? ?Distributed? ?System Software enables computers to coordinate and share The thing being? ?distributed? – Processing logic –... Virtual University of Pakistan History continues ? ?Database? ?Approach: (Also called centralized? ?database) ? ?Database? ?is a shared collection of logically related data Virtual University of Pakistan Database Approach PROGRAM