CS 541 Lecture Slides Sunil Prabhakar CS541 Database Systems

December 8, 2015 Sunil Prabhakar 2 Instructor n Sunil Prabhakar u LWSN 2142C u Office Hours: catch me or by appointment u u n Teaching Assistant: Yasin Silva u u Office hours: TBA u Assignments and Projects

December 8, 2015 Sunil Prabhakar 3 Course Information n Web page: u html html html u Projects, Assignments, Solutions, Slides n alias u Announcements: IMPORTANT u u mailer add me to cs541 n WebCT u Grades u Check that you can log in

December 8, 2015 Sunil Prabhakar 4 Course Description n Introductory graduate course on databases n Fundamental concepts & internals n Some coverage of use of databases (Oracle projects) n Will not teach use of databases!!! n Focus on Relational Databases

December 8, 2015 Sunil Prabhakar 5 Topics n DBMS Concepts and Architecture n Relational Database Model n Relational Languages (Algebra, Calculus, SQL) n Storage and Indexing n Query Processing n Query Optimization n Transaction Processing u Concurrency Control u Recovery n Advanced Topics: TBD (Mining, Indexing, Sensors, …)

December 8, 2015 Sunil Prabhakar 6 Pre-Requisites n Data Structures u Notions of trees, hashing, linked lists etc. n Operating Systems u I/O n Java u Project 3 will be done in Java u RMI u Simple GUI

December 8, 2015 Sunil Prabhakar 7 Text n Database System Concepts (4th Edition) u Silberschatz, Korth, Sudarshan u ISBN: u McGraw Hill n Supplemental Text: u Concurrency Control and Recovery in Database Systems u Bernstein, Hadzilacos, Goodman. u Out of Print: Avaliable free on the Internet u Link from course web page.

December 8, 2015 Sunil Prabhakar 8 Grading Policy n Tentative u Written Assignments (2) 20% u Programming Projects (3-4)40% u Mid-term Exam20% u Final Exam20% n Final not comprehensive n Grading is curved n No extra credit assignments

December 8, 2015 Sunil Prabhakar 9 Academic Integrity n CS Policy u IMPORTANT: visit, read and accept!!! u u Need CS login and password. n Cheating will be taken very seriously. n Make sure that you are familiar with what CS considers to be cheating!! n You may discuss the problems, but the final solution must be your own.

December 8, 2015 Sunil Prabhakar 10 Course Policy n NO LATE SUBMISSIONS n NO EXTENSIONS *** Only on Documented Medical Reasons or Family emergency.

December 8, 2015 Sunil Prabhakar 11 Databases n What is a database? u S/w to manage data. n Why do we need a database? u Ease of development, u Efficiency u Concurrency u Reliability u Ease of administration u Data independence n Importance of databases? u Increasing or decreasing? What is changing?

December 8, 2015 Sunil Prabhakar 12 What is interesting? n Essential to modern applications? u Data is a valuable commodity. n Is there anything challenging? u Encompass PL, OS, Logic, Theory, … u Novel solutions with wider applicability: Transactions, Locking, … n What remains to be done? u Modern applications: Multimedia, Sensors, Streams, Data Warehouses, Data Mining, Privacy and Security, Knowledge, Data on the Web, XML, ….

December 8, 2015 Sunil Prabhakar 13 Abstraction n How to provide a generic, application-independent solution? n Data Models u Abstract view of data u Database efficiently supports this model u Examples: Network, Relational, OO, O-R, … u Most successful model: RELATIONAL n Users access the database as a black box that supports the model. n Languages are used to interact with this Box: u Relational Algebra, SQL,

December 8, 2015 Sunil Prabhakar 14 Independence n Databases allow applications and users to be shielded from the internal details: u Physical data independence F How data is stored (bits, pages, formats, etc.) F Compare with Flat file alternative u Logical data independence F How data is structured logically. F Allows applications to make changes to the logical organization of data without have to rebuild applications

December 8, 2015 Sunil Prabhakar 15 Concurrency Control & Recovery n Two highly desirable requirements: u Enable multiple users to access the data at the same time. u Automatic recovery from crashes. n Challenge: u How to do this in an application-independent manner? n Solution: u Transactions u “Contract” between the DB Black Box and users.

December 8, 2015 Sunil Prabhakar 16 Performance n Critical for databases n Research focus for many years n Must be transparent to the users n Query processing & Optimization n Indexing, storage organization (data independence) n Challenge: u How to optimize without understanding the semantics of an application? n Solution: u Relation data model -- clean mathematical abstraction, allows for alternative equivalent evaluations

December 8, 2015 Sunil Prabhakar 17 This course n Study the relational model, ER model, languages. n Transactions u Concurrency Control u Recovery n Storage and File Structures n Indexing and Hashing n Query Processing and Optimization n Advanced Topics u New data types, applications, multi-dimensional data, data warehousing, data mining, design, …