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We define the data placement problem for a P2P system as follows. Assume we are given a set of cooperating nodes connected by a network (typically, but not necessarily, the Internet) that has limited bandwidth on each link. Nodes know about and exchange data with a collection of participating peers, and they may serve any or all of four roles. The first of these is a data origin, which provides original content to the system and is the authoritative source of that data. As a storage provider, a peer stores materialized views (consuming disk resources, and perhaps replacing previously materialized views if there is insufficient. | ntroduction to Database Systems Module 1 Lecture 1 Instructor Raghu Ramakrishnan raghu@cs.wisc.edu UW-Madison Database Management Systems R. Ramakrishnan 1 What Is a DBMS A very large integrated collection of data. Models real-world enterprise. - Entities e.g. students courses - Relationships e.g. Madonna is taking CS564 A Database Management System DBMS is a software package designed to store and manage databases. Database Management Systems R. Ramakrishnan 2 Why Use a DBMS Data independence and efficient access. Reduced application development time. Data integrity and security. Uniform data administration. Concurrent access recovery from crashes. Database Management Systems R. Ramakrishnan
