* * * Decompositions Do we need to decompose a relation? Several normal forms for relations. If schema in these normal forms certain problems don’t arise The two commonly…

Database Management Systems Chapter 3 The Relational Data Model (III) Instructor: Li Ma Department of Computer Science Texas Southern University, Houston September, 2006…

Schedule Today: Normal Forms. Section 3.6. Next Relational Algebra. Read chapter 5 to page 199 After that SQL Queries. Read Sections 6.1-6.2. J. Holliday - coen 178 Normalization…

* Lecture 7 Design Theory for Relational Databases (part 1) Slides based on http://infolab.stanford.edu/~ullman/fcdb/aut07/index.html#lecture CS4416 Database Systems CS5122…

Normalization Anomalies Boyce-Codd Normal Form 3rd Normal Form Anomalies Goal of relational schema design is to avoid anomalies and redundancy. Update anomaly : one occurrence…

Normalization Anomalies Boyce-Codd Normal Form 3rd Normal Form Source: Slides by Jeffrey Ullman Anomalies Goal of relational schema design is to avoid anomalies and redundancy.…

Closure The closure of {B1…Bk} under the set of FDs S, denoted by {B1…Bk}+, is defined as follows: {B1…Bk}+ = {B | any relation satisfies S will also satisfies B1…BkB}…

Functional Dependencies- Examples Exercise #1: FD’s From DB Instances Below is an instance of R(A1,A2,A3,A4). Choose the FD which may hold on R A4 A1 A2A3  A4 A2A3…

* Loss-Less Joins * Decompositions Dependency-preservation property: enforce constraints on original relation by enforcing some constraints on resulting relations Lossless-join…

Souhad M. Daraghma Functional Dependencies- Examples Exercise #1: FD’s From DB Instances Below is an instance of R(A1,A2,A3,A4). Choose the FD which may hold on R A4 A1…