Database System Concepts 7 th Ed.

Notes

Database System Concepts, 7 th Ed. ©Silberschatz, Korth and Sudarshan See www.db-book.com for conditions on re-use Chapter 7: Normalization Outline ▪ Features of Good Relational Design ▪ Functional Dependencies ▪ Decomposition Using Functional Dependencies ▪ Normal Forms ▪ Functional Dependency Theory ▪ Algorithms for Decomposition using Functional Dependencies ▪ Decomposition Using Multivalued Dependencies ▪ More Normal Form ▪ Atomic Domains and First Normal Form ▪ Database-Design Process ▪ Modeling Temporal Data Overview of Normalization Features of Good Relational Designs ▪ Suppose we combine instructor and department into in_dep, which represents the natural join on the relations instructor and department ▪ There is repetition of information ▪ Need to use null values (if we add a new department with no instructors) A Combined Schema Without Repetition ▪ Consider combining relations sec_class(sec_id, building, room_number) and section(course_id, sec_id, semester, year) into one relation section(course_id, sec_id, semester, year, building, room_number) ▪ No repetition in this case Not all combined schemas result in repetition of information Decomposit...