normalisation Goals: Suppose we have a db scheme: is it good? define precise notions of the qualities of a relational database scheme
|
|
- Mark Ferguson
- 8 years ago
- Views:
Transcription
1 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 to generate good relational database schemes When is a db scheme good anyway? theory 1 2 The Holy Grail of : input: the set of all relevant attributes a set of constraints based on the attribute semantics Requirement 1: Your decomposition should be lossless Requirement 2: Your decomposition should avoid redundancy output: an optimal relational scheme for these attributes 3 4
2 Formalisation of avoiding redundancy: Suppose we have a scheme R and a set FDs F. R is in BCNF (w.r.t. F) iff each left side of a non-trivial FD is a superkey BCNF: Boyce-Codd Normal Form Algorithm: INPUT: a universe R, a set FDs F OUTPUT: a lossless BCNF-decomposition van R METHOD: while there is a scheme S not in BCNF do suppose the villain has left side X let Y = X + without X let Z be the remaining attributes split S(XY Z) into S 1 (XY ), S 2 (XZ) od 5 6 properties of BCNF: BCNF represents the ultimate level of redundancy prevention caused by FDs implementation: in a BCNF schema, the left sides of FDs are keys, so you are able to enforce FDs by defining indexes observation 1: the BCNF decomposition algorithm is not deterministic observation 2: the number of possible BCNF decompositions may be very large observation 3: some BCNF decompositions turn out to be preferable to other BCNF decompositions 7 8
3 The closure of a set FDs F, denoted F +, is the set of all FDs that can be derived from F. Suppose we have a set FD s F and an FD X Y on a scheme R. Question: X Y F +? Method 1: Calculate F + and check whether X Y F +. Expensive! Method 2: Calculate X + and check whether Y X +. This can be done efficiently! 9 Observation: dependency sets may contain redundancy redundant FD: {A B, A C, B C} A C is redundant reducable left side: {A B, AB C} B is superfluous in AB C reducable right side: {A BC, B C} C is superfluous in A BC 10 Two FD-sets F, G are equivalent if F + = G +. We say that these sets cover each other. G is a minimal cover of F if F and G are equivalent and 1. G does not contain redundant FDs 2. all right sides in G are minimal 3. all left sides in G are minimal 11 12
4 Algorithm: INPUT: a set FDs F OUTPUT: a minimal cover for F METHOD: 1. split each FD into single right side FDs 2. reduce left sides 3. eliminate redundant FDs 4. combine FDs with identical left sides Details: 2. reduce left sides: for each FD α β in F do for each attribute A in α do let α = α {A}; if α β can be derived from F then replace α β with α β fi od od Details: Problems with BCNF (continued) 3. eliminate redundant FDs: for each FD α β in F do let F = F {α β}; if α β can be derived from F then delete α β from F od; The projection of FD α β on scheme R is: 1. α β, if αβ attr(r) 2. void, if one of the attributes (left or right) is not in attr(r) 15 16
5 Suppose we have a scheme R and a set FDs F. A decomposition of R into R 1, R 2 is called dependency preserving (DP) if: (F 1 F 2 ) + = F + Examples: R = (ABCDE) F = {A BC, D E} R 1 = (ABC), R 2 = (ADE) Is this decomposition lossless, BCNF, DP? where F i is the projection of F + on R i. R = (ABCDE) F = {A BC, D E} R 1 = (AB), R 2 = (AC), R 3 = (ADE) Is this decomposition lossless, BCNF, DP? 17 R = (ABCDE) F = {A BCDE, C A, D E} R 1 = (ABC), R 2 = (CD), R 3 = (DE) Is this decomposition lossless, BCNF, DP? 18 observation 4: a DP decomposition is preferable to a non DP decomposition, because it enables efficient FD checking observation 5: there does not always exist a DP/BCNF decomposition observation 6: the BCNF decomposition algorithm does not produce always DP decompositions (even if they do exist) Making a choice: Minimize the level of redundancy: BCNF. Accept that the DP property may be lost. or: Allow a bit more redundancy (3NF in stead of BCNF). Enforce the DP property
6 An attribute is prime if it is contained in a candidate key. A relation scheme is in 3NF if for each non trivial FD X A the following condition holds: X is a superkey or A is prime BCNF versus 3NF ADDRESS Street Number Zipcode Ooievaarspad AM Ooievaarspad AM Meerkoetweide AK Meerkoetweide AK Meerkoetweide AL Meerkoetweide AL The following non trivial FDs hold: Street, Number Zipcode Zipcode Street ADDRESS is in 3NF ADDRESS is not in BCNF (redundancy) StrZip Street Zipcode O pad 3403 AM M weide 3403 AK M weide 3403 AL NoZip Number Zipcode AM AM AK AK AL AL StrZip and NoZip are in BCNF. This decomposition is not DP. An operation insert(6, 3403 AK ) on NoZip is incorrect! Detecting this violation requires a join with StrZip. Insert operations should be real time! 3NF-Algorithm: INPUT: a universe R, a set FDs F OUTPUT: a lossless DP 3NF-decomposition of R METHOD: create a minimal cover G from F; generate for each FD X A 1,..., A n a scheme (XA 1 A 2..A n ); if there is a scheme containing a global key K for R, then you are finished else add a global key as an extra relation scheme 23 24
7 overview normal forms normal form feasible complexity 3NF + DP always polynomial BCNF always polynomial BCNF + DP not always NP-hard Requirement 2: you should strive for a high normal form Requirement 3: you should strive for a DP decomposition 25 Multivalued dependencies (MVD) Entity (target) with two unrelated multivalued attributes (company, car) target Charles Charles Andrew Andrew Private investigations target company car Charles Camilla Lamborghini Charles Claudia Maserati Charles Camilla Maserati Charles Claudia Lamborghini Andrew Koo Lamborghini Andrew Claudia Bugatti Andrew Koo Bugatti Andrew Claudia Lamborghini company Camilla Claudia Koo Claudia target car Charles Lamborghini Charles Maserati Andrew Lamborghini Andrew Bugatti 26 Compare: target is spotted with company in car Caught in the act target company car Charles Claudia Lamborghini Charles Camilla Maserati Andrew Koo Bugatti Andrew Claudia Maserati Intuition: A relation r with scheme R(XY Z) obeys the multivalued dependency (MVD) X Y if it is the case that Y and Z each have some connection with X, but do not have anything to do with each other. A relation r with scheme R(XY Z) obeys the multivalued dependency (MVD) X Y if the presence of t 1 and t 2 guarantees the presence of t 3 MVD X Y Z t 1 x y 1 z t 2 x y 2 z t 3 x y 1 z
8 Theorem: Suppose we have a scheme R(XY Z). X Y the decomposition R 1 (XY ), R 2 (XZ) is lossless observation: Suppose we have a scheme R(XY Z). X Y X Y Suppose we have a scheme R(XY Z). We call an MVD X Y trivial if Y X or if Z =. Suppose we have a relation r over a scheme R(XY Z); r is in 4NF if each left side of a non trivial MVD in R is a superkey. observation: Suppose we have a scheme R(XY Z). X Y X Z 29 30
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
More informationLecture 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
More informationRelational 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
More informationDatabase 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
More informationDesign 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
More informationWeek 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
More informationSchema 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
More informationChapter 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
More informationDatabases -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 -
More informationChapter 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
More informationChapter 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
More informationDatabase 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,
More informationSchema 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
More informationObjectives 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
More informationRelational 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:
More informationCOSC344 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
More informationSchema 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
More informationCarnegie 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
More informationRelational 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
More informationFunctional 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
More informationFunctional 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
More informationTheory 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
More informationIntroduction 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
More informationWhy 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
More informationLimitations 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
More informationCS143 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
More informationIntroduction 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
More informationChapter 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
More informationTheory 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
More informationBoyce-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
More informationLimitations 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:
More informationDatabase 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
More informationRelational 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
More informationNormalization 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
More informationDatabase 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
More informationNormalisation 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
More informationChapter 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
More informationTheory 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.
More informationCS 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
More informationIntroduction 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
More informationHow To Find Out What A Key Is In A Database Engine
Database design theory, Part I Functional dependencies Introduction As we saw in the last segment, designing a good database is a non trivial matter. The E/R model gives a useful rapid prototyping tool,
More informationDatabase 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
More informationFunctional 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
More informationChapter 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
More informationTheory 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
More informationFunctional Dependencies
BCNF and 3NF Functional Dependencies Functional dependencies: modeling constraints on attributes stud-id name address course-id session-id classroom instructor Functional dependencies should be obtained
More informationChapter 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
More informationRELATIONAL 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
More informationIntroduction 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,
More informationDesign 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
More informationDATABASE 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
More informationNormalisation. 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
More informationQuiz 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
More informationAdvanced Relational Database Design
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
More informationCSCI-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
More informationNormal 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
More informationJordan 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
More informationRelational 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
More informationNormalization 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
More informationAn 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
More informationDetermination 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,
More informationChapter 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
More informationNormalization. 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
More informationSQL 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.
More information6.830 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)
More informationLecture 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
More informationNormalization 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
More informationMCQs~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
More informationDATABASE DESIGN: NORMALIZATION NOTE & EXERCISES (Up to 3NF)
DATABASE DESIGN: NORMALIZATION NOTE & EXERCISES (Up to 3NF) Tables that contain redundant data can suffer from update anomalies, which can introduce inconsistencies into a database. The rules associated
More informationLiTH, 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
More informationAnnouncements. 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
More informationDatabase 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
More informationNormalization 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
More informationTYPICAL QUESTIONS & ANSWERS
TYPICAL QUESTIONS & ANSWERS PART -I OBJECTIVE TYPE QUESTIONS Each Question carries 2 marks. Choosethe correct or the best alternative in the following: Q.1 Which of the following relational algebra operations
More informationNormalization for Relational DBs
Chapter 7 Functional Dependencies & Normalization for Relational DBs Truong Quynh Chi tqchi@cse.hcmut.edu.vn Spring- 2013 Top-Down Database Design Mini-world Requirements E1 R Relation schemas Conceptual
More informationA 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.
More informationNormalisation in the Presence of Lists
1 Normalisation in the Presence of Lists Sven Hartmann, Sebastian Link Information Science Research Centre, Massey University, Palmerston North, New Zealand 1. Motivation & Revision of the RDM 2. The Brouwerian
More information3. Database Design. 3.1. Functional Dependency. 3.1.01. Introduction. 3.1.02. Value in design. 3.1.03. Initial state. 3.1.05. Aims
of 18 05/03/2007 07:37 3. Database Design This is the Database Design course theme. [Complete set of notes PDF 295Kb]. 3.1. Functional Dependency In this lecture we look at... [Section notes PDF 64Kb]
More informationObjectives, 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
More informationIntroduction to Databases
Introduction to Databases IT University of Copenhagen January 7, 2005 This exam consists of 6 problems with a total of 16 questions. The weight of each problem is stated. You have 4 hours to answer all
More informationDatabase Sample Examination
Part 1: SQL Database Sample Examination (Spring 2007) Question 1: Draw a simple ER diagram that results in a primary key/foreign key constraint to be created between the tables: CREATE TABLE Salespersons
More informationDATABASE 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?
More informationBCA. 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
More informationa 11 x 1 + a 12 x 2 + + a 1n x n = b 1 a 21 x 1 + a 22 x 2 + + a 2n x n = b 2.
Chapter 1 LINEAR EQUATIONS 1.1 Introduction to linear equations A linear equation in n unknowns x 1, x,, x n is an equation of the form a 1 x 1 + a x + + a n x n = b, where a 1, a,..., a n, b are given
More informationModule 5: Normalization of database tables
Module 5: Normalization of database tables Normalization is a process for evaluating and correcting table structures to minimize data redundancies, thereby reducing the likelihood of data anomalies. The
More informationThe 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
More informationChapter 6. Database Tables & Normalization. The Need for Normalization. Database Tables & Normalization
Chapter 6 Database Tables & Normalization Objectives: to learn What normalization is and what role it plays in the database design process About the normal forms 1NF, 2NF, 3NF, BCNF, and 4NF How normal
More informationUnique column combinations
Unique column combinations Arvid Heise Guest lecture in Data Profiling and Data Cleansing Prof. Dr. Felix Naumann Agenda 2 Introduction and problem statement Unique column combinations Exponential search
More informationAbout the Tutorial. Audience. Prerequisites. Copyright & Disclaimer
About the Tutorial Database Management System or DBMS in short refers to the technology of storing and retrieving users data with utmost efficiency along with appropriate security measures. DBMS allows
More informationDatabase Systems I Foundations of Databases
Database Systems I Foundations of Databases Summer term 2010 Melanie Herschel melanie.herschel@uni-tuebingen.de Database Systems Group, University of Tübingen 1 Chapter 4 Normal Forms in the Relational
More informationDiagonalization. Ahto Buldas. Lecture 3 of Complexity Theory October 8, 2009. Slides based on S.Aurora, B.Barak. Complexity Theory: A Modern Approach.
Diagonalization Slides based on S.Aurora, B.Barak. Complexity Theory: A Modern Approach. Ahto Buldas Ahto.Buldas@ut.ee Background One basic goal in complexity theory is to separate interesting complexity
More informationDATABASE 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
More informationA. 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
More informationNormalization. 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.
More informationNormalization Theory for XML
Normalization Theory for XML Marcelo Arenas Department of Computer Science Pontificia Universidad Católica de Chile marenas@ing.puc.cl 1 Introduction Since the beginnings of the relational model, it was
More informationImproving Data Quality: Consistency and Accuracy
Improving Data Quality: Consistency and Accuracy Gao Cong 1 Wenfei Fan 2,3 Floris Geerts 2,4,5 Xibei Jia 2 Shuai Ma 2 1 Microsoft Research Asia 2 University of Edinburgh 4 Hasselt University 3 Bell Laboratories
More informationPart 6. Normalization
Part 6 Normalization Normal Form Overview Universe of All Data Relations (normalized / unnormalized 1st Normal Form 2nd Normal Form 3rd Normal Form Boyce-Codd Normal Form (BCNF) 4th Normal Form 5th Normal
More informationBoolean Algebra (cont d) UNIT 3 BOOLEAN ALGEBRA (CONT D) Guidelines for Multiplying Out and Factoring. Objectives. Iris Hui-Ru Jiang Spring 2010
Boolean Algebra (cont d) 2 Contents Multiplying out and factoring expressions Exclusive-OR and Exclusive-NOR operations The consensus theorem Summary of algebraic simplification Proving validity of an
More informationGraham 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
More informationNormalization. Functional Dependence. Normalization. Normalization. GIS Applications. Spring 2011
Normalization Normalization Normalization is a foundation for relational database design Systematic approach to efficiently organize data in a database GIS Applications Spring 2011 Objectives Minimize
More information