Functional Dependencies

Save this PDF as:
Size: px
Start display at page:

Transcription

1 BCNF and 3NF

2 Functional Dependencies Functional dependencies: modeling constraints on attributes stud-id name address course-id session-id classroom instructor Functional dependencies should be obtained from application requirement analysis Functional dependencies should be maintained for all legal relations in the application CMPT 354: Database I -- BCNF and 3NF 2

3 Closure of Functional Dependencies A set of functional dependencies may logically imply other functional dependencies If A B and B C, then A C The set of all functional dependencies logically implied by F is the closure of F We denote the closure of F by F + F + is a superset of F CMPT 354: Database I -- BCNF and 3NF 3

4 Armstrong s Axioms Finding F + (reflexivity) If β α, then α β (augmentation) If α β, then γ α γβ (transitivity) If α β, and β γ, then α γ These rules are Sound: generate only functional dependencies that actually hold Complete: generate all functional dependencies that hold CMPT 354: Database I -- BCNF and 3NF 4

5 Computing Closure F + = F repeat for each functional dependency f in F + apply reflexivity and augmentation rules on f add the resulting functional dependencies to F + for each pair of functional dependencies f 1 and f 2 in F + if f 1 and f 2 can be combined using transitivity then add the resulting functional dependency to F + until F + does not change any further CMPT 354: Database I -- BCNF and 3NF 5

6 Problem of Non-Key Dependencies bor_loan(customer_id, loan_number, amount) loan_number amount, but loan_number customer_id does not hold The amount information repeats unnecessarily Is loan_number also redundant? CMPT 354: Database I -- BCNF and 3NF 6

7 Update and Deletion Anomalies bor_loan(customer_id, loan_number, amount) Update anomalies: if the amount of a loan is changed and the loan has n customers, the n tuples have to be updated Deletion anomalies: if a loan having n customers is deleted, we have to delete n tuples The amount information has to be deleted n times Failing to update/delete all tuple leads to inconsistency CMPT 354: Database I -- BCNF and 3NF 7

8 Reducing Redundancy Make a table loan(loan_number, amount) where loan_number is the key Rename bor_loan to borrower(customer_id, loan_number) where (customer_id, loan_number) is the key No information loss by joining on loan_number Update/deletion anomalies are eliminated CMPT 354: Database I -- BCNF and 3NF 8

9 Boyce-Codd Normal Form A relation schema R is in BCNF if for all functional dependencies in F + of the form α β at least one of the following holds α β is trivial (i.e., β α) α is a superkey for R bor_loan = (customer_id, loan_number, amount) is not in BCNF loan_number amount holds on bor_loan but loan_number is not a superkey CMPT 354: Database I -- BCNF and 3NF 9

10 Decomposing into BCNF For schema R and a non-trivial dependency α β causes a violation of BCNF, decompose R into (α U β ): α is the key (R -( β - α )) bor_loan = (customer_id, loan_number, amount), loan_number amount (loan_number, amount ) (customer_id, loan_number) CMPT 354: Database I -- BCNF and 3NF 10

11 Missing Functional Dependencies cust_banker_branch(customer_id, employee_id, branch_name, type) R1: employee_id branch_name R2: customer_id, branch_name employee_id Not in BCNF, decompose into banker_branch(employee_id, branch_name) cust_banker(customer_id, employee_id, type) Functional dependency R2 is lost CMPT 354: Database I -- BCNF and 3NF 11

12 Insertion Anomalies Decompose cust_banker_branch(customer_id, employee_id, branch_name, type) into banker_branch(employee_id, branch_name) and cust_banker(customer_id, employee_id, type) Cannot insert (c1, e1, Burnaby, loan) and (c1, e2, Burnaby, loan) into cust_banker_branch R2: customer_id, branch_name employee_id is violated CMPT 354: Database I -- BCNF and 3NF 12

13 Insertion Anomalies Decompose cust_banker_branch(customer_id, employee_id, branch_name, type) into banker_branch(employee_id, branch_name) and cust_banker(customer_id, employee_id, type) Can insert (e1, Burnaby) (e2, Burnaby) into banker_branch, and (c1, e1, loan) and (c1, e2, loan) into cust_banker (c1, e1, Burnaby, loan) and (c1, e2, Burnaby, loan) are inserted into the join of banker_branch and cust_banker CMPT 354: Database I -- BCNF and 3NF 13

14 BCNF and Insertion Anomalies Decomposition to BCNF may lose some functional dependencies The lost functional dependencies lead to insertion anomalies CMPT 354: Database I -- BCNF and 3NF 14

15 BCNF and Dependency Preservation If it is sufficient to test only those dependencies on each individual relation of a decomposition in order to ensure that all functional dependencies hold, then that decomposition is dependency preserving Constraints, including functional dependencies, are costly to check in practice unless they pertain to only one relation joining multiple tables is costly BCNF may not preserve functional dependencies Consider a weaker normal form if functional dependencies cannot be preserved in BCNF CMPT 354: Database I -- BCNF and 3NF 15

16 Decomposition for Preservation Banker-info-schema = (branch-name, customername, banker-name, office-number) R1:banker-name branch-name office-number R2:customer-name branch-name banker-name Decomposition preserving all functional dependencies Banker-office-schema = (banker-name, branch-name, office-number), preserving R1 Banker-schema = (customer-name, branch-name, banker-name), preserving R2 (banker-name, branch-name) is repeated in both tables CMPT 354: Database I -- BCNF and 3NF 16

17 Third Normal Form A relation schema R is in the third normal form (3NF) if for all α β in F + at least one of the following holds α β is trivial (i.e., β α) α is a superkey for R Each attribute A in β α is contained in a candidate key for R Each attribute may be in a different candidate key If a relation is in BCNF it is in 3NF In BCNF one of the first two conditions above must hold The third condition is a minimal relaxation of BCNF to ensure dependency preservation CMPT 354: Database I -- BCNF and 3NF 17

18 Comparison of BCNF and 3NF It is always possible to decompose a relation into a set of relations that are in 3NF such that the decomposition is lossless and the dependencies are preserved It is always possible to decompose a relation into a set of relations that are in BCNF such that the decomposition is lossless It may not be possible to preserve all functional dependencies CMPT 354: Database I -- BCNF and 3NF 18

19 Design Goals Goal for a relational database design is BCNF Lossless join Dependency preservation If we cannot achieve all, we have to trade off between Lack of dependency preservation Redundancy due to use of 3NF CMPT 354: Database I -- BCNF and 3NF 19

20 Functional Dependencies and SQL SQL does not provide a direct way of specifying functional dependencies other than superkeys Can specify FDs using assertions, but they are expensive to test Even if we had a dependency preserving decomposition, using SQL we would not be able to efficiently test a functional dependency whose left hand side is not a key CMPT 354: Database I -- BCNF and 3NF 20

21 Summary Non-key dependencies causes redundancy and anomalies BCNF lossless decomposition, but may not preserve all functional dependencies 3NF lossless decomposition preserving all functional dependencies, but may still contain some redundancy CMPT 354: Database I -- BCNF and 3NF 21

22 To-Do-List Read Section 7.3 in the textbook Given a relation R, a set of functional dependencies F, and a decomposition of R how can we determine whether the decomposition is in BCNF? How can we determine whether the decomposition is in 3NF? CMPT 354: Database I -- BCNF and 3NF 22

Chapter 7: Relational Database Design

Chapter 7: Relational Database Design Database System Concepts, 5th Ed. See www.db book.com for conditions on re use Chapter 7: Relational Database Design Features of Good Relational Design Atomic Domains

Boyce-Codd Normal Form

4NF Boyce-Codd Normal Form A relation schema R is in BCNF if for all functional dependencies in F + of the form α β at least one of the following holds α β is trivial (i.e., β α) α is a superkey for R

Chapter 7: Relational Database Design

Chapter 7: Relational Database Design Pitfalls in Relational Database Design Decomposition Normalization Using Functional Dependencies Normalization Using Multivalued Dependencies Normalization Using Join

CS 377 Database Systems. Database Design Theory and Normalization. Li Xiong Department of Mathematics and Computer Science Emory University

CS 377 Database Systems Database Design Theory and Normalization Li Xiong Department of Mathematics and Computer Science Emory University 1 Relational database design So far Conceptual database design

Database Design and Normalization

Database Design and Normalization CPS352: Database Systems Simon Miner Gordon College Last Revised: 9/27/12 Agenda Check-in Functional Dependencies (continued) Design Project E-R Diagram Presentations

Relational Database Design: FD s & BCNF

CS145 Lecture Notes #5 Relational Database Design: FD s & BCNF Motivation Automatic translation from E/R or ODL may not produce the best relational design possible Sometimes database designers like to

Schema Design and Normal Forms Sid Name Level Rating Wage Hours

Entity-Relationship Diagram Schema Design and Sid Name Level Rating Wage Hours Database Management Systems, 2 nd Edition. R. Ramakrishnan and J. Gehrke 1 Database Management Systems, 2 nd Edition. R. Ramakrishnan

Design of Relational Database Schemas

Design of Relational Database Schemas T. M. Murali October 27, November 1, 2010 Plan Till Thanksgiving What are the typical problems or anomalies in relational designs? Introduce the idea of decomposing

Limitations of E-R Designs. Relational Normalization Theory. Redundancy and Other Problems. Redundancy. Anomalies. Example

Limitations of E-R Designs Relational Normalization Theory Chapter 6 Provides a set of guidelines, does not result in a unique database schema Does not provide a way of evaluating alternative schemas Normalization

Chapter 10 Functional Dependencies and Normalization for Relational Databases

Chapter 10 Functional Dependencies and Normalization for Relational Databases Copyright 2004 Pearson Education, Inc. Chapter Outline 1 Informal Design Guidelines for Relational Databases 1.1Semantics of

Theory of Relational Database Design and Normalization

Theory of Relational Database Design and Normalization (Based on Chapter 14 and some part of Chapter 15 in Fundamentals of Database Systems by Elmasri and Navathe) 1 Informal Design Guidelines for Relational

Functional Dependencies and Finding a Minimal Cover

Functional Dependencies and Finding a Minimal Cover Robert Soulé 1 Normalization An anomaly occurs in a database when you can update, insert, or delete data, and get undesired side-effects. These side

Schema Refinement and Normalization

Schema Refinement and Normalization Module 5, Lectures 3 and 4 Database Management Systems, R. Ramakrishnan 1 The Evils of Redundancy Redundancy is at the root of several problems associated with relational

Why Is This Important? Schema Refinement and Normal Forms. The Evils of Redundancy. Functional Dependencies (FDs) Example (Contd.)

Why Is This Important? Schema Refinement and Normal Forms Chapter 19 Many ways to model a given scenario in a database How do we find the best one? We will discuss objective criteria for evaluating database

Schema Refinement, Functional Dependencies, Normalization

Schema Refinement, Functional Dependencies, Normalization MSCI 346: Database Systems Güneş Aluç, University of Waterloo Spring 2015 MSCI 346: Database Systems Chapter 19 1 / 42 Outline 1 Introduction Design

Chapter 10. Functional Dependencies and Normalization for Relational Databases

Chapter 10 Functional Dependencies and Normalization for Relational Databases Chapter Outline 1 Informal Design Guidelines for Relational Databases 1.1Semantics of the Relation Attributes 1.2 Redundant

Relational Database Design

Relational Database Design To generate a set of relation schemas that allows - to store information without unnecessary redundancy - to retrieve desired information easily Approach - design schema in appropriate

Theory of Relational Database Design and Normalization

Theory of Relational Database Design and Normalization (Based on Chapter 14 and some part of Chapter 15 in Fundamentals of Database Systems by Elmasri and Navathe, Ed. 3) 1 Informal Design Guidelines for

Fundamentals of Database System

Fundamentals of Database System Chapter 4 Normalization Fundamentals of Database Systems (Chapter 4) Page 1 Introduction To Normalization In general, the goal of a relational database design is to generate

Relational Database Design Theory

Relational Database Design Theory Informal guidelines for good relational designs Functional dependencies Normal forms and normalization 1NF, 2NF, 3NF BCNF, 4NF, 5NF Inference rules on functional dependencies

Week 11: Normal Forms. Logical Database Design. Normal Forms and Normalization. Examples of Redundancy

Week 11: Normal Forms Database Design Database Redundancies and Anomalies Functional Dependencies Entailment, Closure and Equivalence Lossless Decompositions The Third Normal Form (3NF) The Boyce-Codd

COSC344 Database Theory and Applications. Lecture 9 Normalisation. COSC344 Lecture 9 1

COSC344 Database Theory and Applications Lecture 9 Normalisation COSC344 Lecture 9 1 Overview Last Lecture Functional Dependencies This Lecture Normalisation Introduction 1NF 2NF 3NF BCNF Source: Section

Limitations of DB Design Processes

Normalization CS 317/387 1 Limitations of DB Design Processes Provides a set of guidelines, does not result in a unique database schema Does not provide a way of evaluating alternative schemas Pitfalls:

Chapter 5: Logical Database Design and the Relational Model Part 2: Normalization. Introduction to Normalization. Normal Forms.

Chapter 5: Logical Database Design and the Relational Model Part 2: Normalization Modern Database Management 6 th Edition Jeffrey A. Hoffer, Mary B. Prescott, Fred R. McFadden Robert C. Nickerson ISYS

Database Design and Normal Forms

Database Design and Normal Forms Database Design coming up with a good schema is very important How do we characterize the goodness of a schema? If two or more alternative schemas are available how do

Database Management System

UNIT -6 Database Design Informal Design Guidelines for Relation Schemas; Functional Dependencies; Normal Forms Based on Primary Keys; General Definitions of Second and Third Normal Forms; Boyce-Codd Normal

Chapter 15 Basics of Functional Dependencies and Normalization for Relational Databases

Chapter 15 Basics of Functional Dependencies and Normalization for Relational Databases Copyright 2011 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Chapter 15 Outline Informal Design Guidelines

We know how to query a database using SQL. A set of tables and their schemas are given Data are properly loaded

E-R Diagram Database Development We know how to query a database using SQL A set of tables and their schemas are given Data are properly loaded But, how can we develop appropriate tables and their schema

Announcements. SQL is hot! Facebook. Goal. Database Design Process. IT420: Database Management and Organization. Normalization (Chapter 3)

Announcements IT0: Database Management and Organization Normalization (Chapter 3) Department coin design contest deadline - February -week exam Monday, February 1 Lab SQL SQL Server: ALTER TABLE tname

DATABASE NORMALIZATION

DATABASE NORMALIZATION Normalization: process of efficiently organizing data in the DB. RELATIONS (attributes grouped together) Accurate representation of data, relationships and constraints. Goal: - Eliminate

normalisation Goals: Suppose we have a db scheme: is it good? define precise notions of the qualities of a relational database scheme

Goals: Suppose we have a db scheme: is it good? Suppose we have a db scheme derived from an ER diagram: is it good? define precise notions of the qualities of a relational database scheme define algorithms

CS143 Notes: Normalization Theory

CS143 Notes: Normalization Theory Book Chapters (4th) Chapters 7.1-6, 7.8, 7.10 (5th) Chapters 7.1-6, 7.8 (6th) Chapters 8.1-6, 8.8 INTRODUCTION Main question How do we design good tables for a relational

Database Management Systems. Redundancy and Other Problems. Redundancy

Database Management Systems Winter 2004 CMPUT 391: Database Design Theory or Relational Normalization Theory Dr. Osmar R. Zaïane Lecture 2 Limitations of Relational Database Designs Provides a set of guidelines,

Database Constraints and Design

Database Constraints and Design We know that databases are often required to satisfy some integrity constraints. The most common ones are functional and inclusion dependencies. We ll study properties of

Theory behind Normalization & DB Design. Satisfiability: Does an FD hold? Lecture 12

Theory behind Normalization & DB Design Lecture 12 Satisfiability: Does an FD hold? Satisfiability of FDs Given: FD X Y and relation R Output: Does R satisfy X Y? Algorithm: a.sort R on X b.do all the

Normalisation to 3NF. Database Systems Lecture 11 Natasha Alechina

Normalisation to 3NF Database Systems Lecture 11 Natasha Alechina In This Lecture Normalisation to 3NF Data redundancy Functional dependencies Normal forms First, Second, and Third Normal Forms For more

Normalization in Database Design

in Database Design Marek Rychly mrychly@strathmore.edu Strathmore University, @ilabafrica & Brno University of Technology, Faculty of Information Technology Advanced Databases and Enterprise Systems 14

Functional Dependencies and Normalization

Functional Dependencies and Normalization 5DV119 Introduction to Database Management Umeå University Department of Computing Science Stephen J. Hegner hegner@cs.umu.se http://www.cs.umu.se/~hegner Functional

Lecture Notes on Database Normalization

Lecture Notes on Database Normalization Chengkai Li Department of Computer Science and Engineering The University of Texas at Arlington April 15, 2012 I decided to write this document, because many students

Database Systems Concepts, Languages and Architectures

These slides are for use with Database Systems Concepts, Languages and Architectures Paolo Atzeni Stefano Ceri Stefano Paraboschi Riccardo Torlone To view these slides on-screen or with a projector use

MCQs~Databases~Relational Model and Normalization http://en.wikipedia.org/wiki/database_normalization

http://en.wikipedia.org/wiki/database_normalization Database normalization is the process of organizing the fields and tables of a relational database to minimize redundancy. Normalization usually involves

Databases -Normalization III. (N Spadaccini 2010 and W Liu 2012) Databases - Normalization III 1 / 31

Databases -Normalization III (N Spadaccini 2010 and W Liu 2012) Databases - Normalization III 1 / 31 This lecture This lecture describes 3rd normal form. (N Spadaccini 2010 and W Liu 2012) Databases -

Introduction to SQL (3.1-3.4)

CSL 451 Introduction to Database Systems Introduction to SQL (3.1-3.4) Department of Computer Science and Engineering Indian Institute of Technology Ropar Narayanan (CK) Chatapuram Krishnan! Summary Parts

Chapter 5: FUNCTIONAL DEPENDENCIES AND NORMALIZATION FOR RELATIONAL DATABASES

1 Chapter 5: FUNCTIONAL DEPENDENCIES AND NORMALIZATION FOR RELATIONAL DATABASES INFORMAL DESIGN GUIDELINES FOR RELATION SCHEMAS We discuss four informal measures of quality for relation schema design in

Introduction to Database Systems. Normalization

Introduction to Database Systems Normalization Werner Nutt 1 Normalization 1. Anomalies 1. Anomalies 2. Boyce-Codd Normal Form 3. 3 rd Normal Form 2 Anomalies The goal of relational schema design is to

APPENDIX B Advanced Relational Database Design In this appendix we cover advanced topics in relational database design. We first present the theory of multivalued dependencies, including a set of sound

Carnegie Mellon Univ. Dept. of Computer Science 15-415 - Database Applications. Overview - detailed. Goal. Faloutsos CMU SCS 15-415

Faloutsos 15-415 Carnegie Mellon Univ. Dept. of Computer Science 15-415 - Database Applications Lecture #17: Schema Refinement & Normalization - Normal Forms (R&G, ch. 19) Overview - detailed DB design

Functional Dependency and Normalization for Relational Databases

Functional Dependency and Normalization for Relational Databases Introduction: Relational database design ultimately produces a set of relations. The implicit goals of the design activity are: information

Chapter 8. Database Design II: Relational Normalization Theory

Chapter 8 Database Design II: Relational Normalization Theory The E-R approach is a good way to start dealing with the complexity of modeling a real-world enterprise. However, it is only a set of guidelines

Design Theory for Relational Databases: Functional Dependencies and Normalization

Design Theory for Relational Databases: Functional Dependencies and Normalization Juliana Freire Some slides adapted from L. Delcambre, R. Ramakrishnan, G. Lindstrom, J. Ullman and Silberschatz, Korth

Normalization. CIS 331: Introduction to Database Systems

Normalization CIS 331: Introduction to Database Systems Normalization: Reminder Why do we need to normalize? To avoid redundancy (less storage space needed, and data is consistent) To avoid update/delete

Introduction to Database Systems. Chapter 4 Normal Forms in the Relational Model. Chapter 4 Normal Forms

Introduction to Database Systems Winter term 2013/2014 Melanie Herschel melanie.herschel@lri.fr Université Paris Sud, LRI 1 Chapter 4 Normal Forms in the Relational Model After completing this chapter,

Normalization in OODB Design

Normalization in OODB Design Byung S. Lee Graduate Programs in Software University of St. Thomas St. Paul, Minnesota bslee@stthomas.edu Abstract When we design an object-oriented database schema, we need

Chapter 6: Integrity Constraints

Chapter 6: Integrity Constraints Domain Constraints Referential Integrity Assertions Triggers Functional Dependencies Database Systems Concepts 6.1 Silberschatz, Korth and Sudarshan c 1997 Domain Constraints

A. TRUE-FALSE: GROUP 2 PRACTICE EXAMPLES FOR THE REVIEW QUIZ:

GROUP 2 PRACTICE EXAMPLES FOR THE REVIEW QUIZ: Review Quiz will contain very similar question as below. Some questions may even be repeated. The order of the questions are random and are not in order of

Introduction Decomposition Simple Synthesis Bernstein Synthesis and Beyond. 6. Normalization. Stéphane Bressan. January 28, 2015

6. Normalization Stéphane Bressan January 28, 2015 1 / 42 This lecture is based on material by Professor Ling Tok Wang. CS 4221: Database Design The Relational Model Ling Tok Wang National University of

SQL DDL. DBS Database Systems Designing Relational Databases. Inclusion Constraints. Key Constraints

DBS Database Systems Designing Relational Databases Peter Buneman 12 October 2010 SQL DDL In its simplest use, SQL s Data Definition Language (DDL) provides a name and a type for each column of a table.

Objectives of Database Design Functional Dependencies 1st Normal Form Decomposition Boyce-Codd Normal Form 3rd Normal Form Multivalue Dependencies

Objectives of Database Design Functional Dependencies 1st Normal Form Decomposition Boyce-Codd Normal Form 3rd Normal Form Multivalue Dependencies 4th Normal Form General view over the design process 1

Theory I: Database Foundations

Theory I: Database Foundations 19. 19. Theory I: Database Foundations 07.2012 1 Theory I: Database Foundations 20. Formal Design 20. 20: Formal Design We want to distinguish good from bad database design.

ER modelling, Weak Entities, Class Hierarchies, Aggregation

CS344 Database Management Systems ER modelling, Weak Entities, Class Hierarchies, Aggregation Aug 2 nd - Lecture Notes (Summary) Submitted by - N. Vishnu Teja Saurabh Saxena 09010125 09010145 (Most the

Normalization of database model. Pazmany Peter Catholic University 2005 Zoltan Fodroczi

Normalization of database model Pazmany Peter Catholic University 2005 Zoltan Fodroczi Closure of an attribute set Given a set of attributes α define the closure of attribute set α under F (denoted as

LiTH, Tekniska högskolan vid Linköpings universitet 1(7) IDA, Institutionen för datavetenskap Juha Takkinen 2007-05-24

LiTH, Tekniska högskolan vid Linköpings universitet 1(7) IDA, Institutionen för datavetenskap Juha Takkinen 2007-05-24 1. A database schema is a. the state of the db b. a description of the db using a

Introduction to normalization. Introduction to normalization

Introduction to normalization Lecture 4 Instructor Anna Sidorova Agenda Presentation Review of relational models, in class exersise Introduction to normalization In-class exercises Discussion of HW2 1

Determination of the normalization level of database schemas through equivalence classes of attributes

Computer Science Journal of Moldova, vol.17, no.2(50), 2009 Determination of the normalization level of database schemas through equivalence classes of attributes Cotelea Vitalie Abstract In this paper,

Chapter 10. Functional Dependencies and Normalization for Relational Databases. Copyright 2007 Ramez Elmasri and Shamkant B.

Chapter 10 Functional Dependencies and Normalization for Relational Databases Copyright 2007 Ramez Elmasri and Shamkant B. Navathe Chapter Outline 1 Informal Design Guidelines for Relational Databases

A Web-Based Environment for Learning Normalization of Relational Database Schemata

A Web-Based Environment for Learning Normalization of Relational Database Schemata Nikolay Georgiev September 2008 Master s Thesis in Computing Science, 30 ECTS credits Supervisor at CS-UmU: Stephen J.

B2.2-R3: INTRODUCTION TO DATABASE MANAGEMENT SYSTEMS

B2.2-R3: INTRODUCTION TO DATABASE MANAGEMENT SYSTEMS NOTE: 1. There are TWO PARTS in this Module/Paper. PART ONE contains FOUR questions and PART TWO contains FIVE questions. 2. PART ONE is to be answered

Comp 5311 Database Management Systems. 3. Structured Query Language 1

Comp 5311 Database Management Systems 3. Structured Query Language 1 1 Aspects of SQL Most common Query Language used in all commercial systems Discussion is based on the SQL92 Standard. Commercial products

CSCI-GA.2433-001 Database Systems Lecture 7: Schema Refinement and Normalization

CSCI-GA.2433-001 Database Systems Lecture 7: Schema Refinement and Normalization Mohamed Zahran (aka Z) mzahran@cs.nyu.edu http://www.mzahran.com View 1 View 2 View 3 Conceptual Schema At that point we

Simple SQL Queries (3)

Simple SQL Queries (3) What Have We Learned about SQL? Basic SELECT-FROM-WHERE structure Selecting from multiple tables String operations Set operations Aggregate functions and group-by queries Null values

Introduction to Databases, Fall 2005 IT University of Copenhagen. Lecture 5: Normalization II; Database design case studies. September 26, 2005

Introduction to Databases, Fall 2005 IT University of Copenhagen Lecture 5: Normalization II; Database design case studies September 26, 2005 Lecturer: Rasmus Pagh Today s lecture Normalization II: 3rd

RELATIONAL DATABASE DESIGN

RELATIONAL DATABASE DESIGN g Good database design - Avoiding anomalies g Functional Dependencies g Normalization & Decomposition Using Functional Dependencies g 1NF - Atomic Domains and First Normal Form

The University of British Columbia

The University of British Columbia Computer Science 304 Midterm Examination October 31, 2005 Time: 50 minutes Total marks: 50 Instructor: Rachel Pottinger Name ANSWER KEY (PRINT) (Last) (First) Signature

Objectives, outcomes, and key concepts. Objectives: give an overview of the normal forms and their benefits and problems.

Normalization Page 1 Objectives, outcomes, and key concepts Tuesday, January 6, 2015 11:45 AM Objectives: give an overview of the normal forms and their benefits and problems. Outcomes: students should

DATABASE MANAGEMENT SYSTEMS. Question Bank:

DATABASE MANAGEMENT SYSTEMS Question Bank: UNIT 1 1. Define Database? 2. What is a DBMS? 3. What is the need for database systems? 4. Define tupule? 5. What are the responsibilities of DBA? 6. Define schema?

Normalisation. Why normalise? To improve (simplify) database design in order to. Avoid update problems Avoid redundancy Simplify update operations

Normalisation Why normalise? To improve (simplify) database design in order to Avoid update problems Avoid redundancy Simplify update operations 1 Example ( the practical difference between a first normal

Normalization of Database

Normalization of Database UNIT-4 Database Normalisation is a technique of organizing the data in the database. Normalization is a systematic approach of decomposing tables to eliminate data redundancy

6.830 Lecture 3 9.16.2015 PS1 Due Next Time (Tuesday!) Lab 1 Out today start early! Relational Model Continued, and Schema Design and Normalization

6.830 Lecture 3 9.16.2015 PS1 Due Next Time (Tuesday!) Lab 1 Out today start early! Relational Model Continued, and Schema Design and Normalization Animals(name,age,species,cageno,keptby,feedtime) Keeper(id,name)

Normal forms and normalization

Normal forms and normalization An example of normalization using normal forms We assume we have an enterprise that buys products from different supplying companies, and we would like to keep track of our

Lesson 8: Introduction to Databases E-R Data Modeling

Lesson 8: Introduction to Databases E-R Data Modeling Contents Introduction to Databases Abstraction, Schemas, and Views Data Models Database Management System (DBMS) Components Entity Relationship Data

Normalization. Normalization. Normalization. Data Redundancy

Normalization Normalization o Main objective in developing a logical data model for relational database systems is to create an accurate representation of the data, its relationships, and constraints.

The class slides, your notes, and the sample problem that we worked in class may be helpful for reference.

Page 1 of 5 Normalization Lab 12 and Take-home Exam II Objective The goal of this lab is to give you more practice on normalizing a database. You will analyze an existing database to determine the changes

Relational Normalization Theory (supplemental material)

Relational Normalization Theory (supplemental material) CSE 532, Theory of Database Systems Stony Brook University http://www.cs.stonybrook.edu/~cse532 2 Quiz 8 Consider a schema S with functional dependencies:

An Algorithmic Approach to Database Normalization

An Algorithmic Approach to Database Normalization M. Demba College of Computer Science and Information Aljouf University, Kingdom of Saudi Arabia bah.demba@ju.edu.sa ABSTRACT When an attempt is made to

Graham Kemp (telephone 772 54 11, room 6475 EDIT) The examiner will visit the exam room at 15:00 and 17:00.

CHALMERS UNIVERSITY OF TECHNOLOGY Department of Computer Science and Engineering Examination in Databases, TDA357/DIT620 Tuesday 17 December 2013, 14:00-18:00 Examiner: Results: Exam review: Grades: Graham

Database Design and Normalization

Database Design and Normalization Chapter 10 (Week 11) EE562 Slides and Modified Slides from Database Management Systems, R. Ramakrishnan 1 Computing Closure F + Example: List all FDs with: - a single

Lecture 2 Normalization

MIT 533 ระบบฐานข อม ล 2 Lecture 2 Normalization Walailuk University Lecture 2: Normalization 1 Objectives The purpose of normalization The identification of various types of update anomalies The concept

Advance DBMS. Structured Query Language (SQL)

Structured Query Language (SQL) Introduction Commercial database systems use more user friendly language to specify the queries. SQL is the most influential commercially marketed product language. Other

Question 1. Relational Data Model [17 marks] Question 2. SQL and Relational Algebra [31 marks]

EXAMINATIONS 2005 MID-YEAR COMP 302 Database Systems Time allowed: Instructions: 3 Hours Answer all questions. Make sure that your answers are clear and to the point. Write your answers in the spaces provided.

Jordan University of Science & Technology Computer Science Department CS 728: Advanced Database Systems Midterm Exam First 2009/2010

Jordan University of Science & Technology Computer Science Department CS 728: Advanced Database Systems Midterm Exam First 2009/2010 Student Name: ID: Part 1: Multiple-Choice Questions (17 questions, 1

Normalization. CIS 3730 Designing and Managing Data. J.G. Zheng Fall 2010

Normalization CIS 3730 Designing and Managing Data J.G. Zheng Fall 2010 1 Overview What is normalization? What are the normal forms? How to normalize relations? 2 Two Basic Ways To Design Tables Bottom-up:

BCA. Database Management System

BCA IV Sem Database Management System Multiple choice questions 1. A Database Management System (DBMS) is A. Collection of interrelated data B. Collection of programs to access data C. Collection of data

DATABASE SYSTEMS. Chapter 7 Normalisation

DATABASE SYSTEMS DESIGN IMPLEMENTATION AND MANAGEMENT INTERNATIONAL EDITION ROB CORONEL CROCKETT Chapter 7 Normalisation 1 (Rob, Coronel & Crockett 978184480731) In this chapter, you will learn: What normalization

Relational Normalization: Contents. Relational Database Design: Rationale. Relational Database Design. Motivation

Relational Normalization: Contents Motivation Functional Dependencies First Normal Form Second Normal Form Third Normal Form Boyce-Codd Normal Form Decomposition Algorithms Multivalued Dependencies and

Quiz 3: Database Systems I Instructor: Hassan Khosravi Spring 2012 CMPT 354

Quiz 3: Database Systems I Instructor: Hassan Khosravi Spring 2012 CMPT 354 1. [10] Show that each of the following are not valid rules about FD s by giving a small example relations that satisfy the given

Comp 3311 Database Management Systems. 2. Relational Model Exercises

Comp 3311 Database Management Systems 2. Relational Model Exercises 1 E-R Diagram for a Banking Enterprise 2 Tables for ER diagram Entities Branch (branch-name, branch-city, assets) Customer (customer-id,

Normalisation and Data Storage Devices

Unit 4 Normalisation and Data Storage Devices Structure 4.1 Introduction 4.2 Functional Dependency 4.3 Normalisation 4.3.1 Why do we Normalize a Relation? 4.3.2 Second Normal Form Relation 4.3.3 Third

Topic 5.1: Database Tables and Normalization

Topic 5.1: Database Tables and Normalization What is Normalization? Normalization is a process for evaluating and correcting table structures to minimize data redundancies, thereby helping to eliminate