CS 34800 Chapter Notes - Chapter 1: Physical Data Model, Logical Data Model, Ntfs

• School: Purdue University
• Department: Computer Sciences
• Course: CS 34800
• Professor: Chris Clifton

Document Summary

Physical schema refers to how we represent and store the data, what kind of secondary storage,file systems etc are we using. Logical schema refers to how we represent the data in terms of data structures like tables, columns, classes etc. If you want to grant different access privileges to different users using your system, or want users to see only the data relevant to them. Cs department with different positions (professor, head of department, ta"s: if you want to safely manage concurrent access to a certain data without losing data integrity. The atomicity aspect of a database makes sure that the order in concurrent access is irrelevant, and updates rollback if a concurrent transaction fails. File systems can"t do it reliably, and are more suitable for sequential accesses in most cases. e. g. a bank account, a airline ticket reservation system etc. Your list of movies to watch in a txt file, photos from your recent holiday trip etc.