'Update anomalies' diaporamas de présentation

Schema Refinement and Normal Forms

Schema Refinement and Normal Forms. Review: Database Design. Requirements Analysis user needs; what must database do? Conceptual Design high level description (often done w/ER model) Logical Design translate ER into DBMS data model Schema Refinement consistency, normalization

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B. Information Technology (Hons.) CMPB245: Database Design

B. Information Technology (Hons.) CMPB245: Database Design. Normalization Pt. 1. Objectives. Explain the purpose of normalization and the problems associated with redundant information Identify the types of update anomalies Explain the concept of functional dependency.

1.02k views • 88 slides

CS 728 Advanced Database Systems Chapter 14

CS 728 Advanced Database Systems Chapter 14. Database Design Theory: Introduction to Normalization Using Functional & Multivalued Dependencies. Design Guidelines for Relation Schemas. 1. Attributes should have clear meanings (semantics) and related attributes are grouped into single entities.

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Outline: Normalization

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Boyce-Codd NF & Lossless Decomposition

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CHAPTER 19 SCHEMA, REFINEMENT AND NORMAL FORMS

CHAPTER 19 SCHEMA, REFINEMENT AND NORMAL FORMS. INTRODUCTION. Having defined all the relational schemas that we want in our database, the next step is to refine them for so as to (near)optimize them with respect to (memory) space and time (of response to queries).

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Normalization in Databases

Normalization in Databases. What is Normalization?. Unnormalized data exists in flat files Normalization is the process of moving data into related tables

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CHAPTER 19 SCHEMA, REFINEMENT AND NORMAL FORMS

CHAPTER 19 SCHEMA, REFINEMENT AND NORMAL FORMS. INTRODUCTION. Having defined all the relational schemas that we want in our database, the next step is to refine them for so as to (near)optimize them with respect to (memory) space and time (of response to queries).

499 views • 36 slides

Fourth normal form: 4NF

Fourth normal form: 4NF. Normal forms. desirable forms for relations in DB design eliminate redundancies avoid update anomalies enforce integrity constraints in one sentence: produce a good representation of the real world formally defined, based on semantic concepts not a panacea.

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Functional Dependencies and Normalization

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Functional Dependencies and Normalization

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Chapter 5

Chapter 5. Database Design 1: Normalization. Objectives. Discuss functional dependence Define first normal form, second normal form, and third normal form

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The One-to-Many Relationship

The One-to-Many Relationship. Cow of many-well milked and badly fed Spanish proverb. The one-to-many relationship. Entities are related to other entities A 1:m relationship. Hierarchical relationships. Occur frequently Multiple 1:m relationships.

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Database Design

Database Design. Conceptual identify important entities and relationships determine attribute domains and candidate keys draw the E-R diagram Logical validate model using normalization Physical implement on DBMS. Logical Design. Split data into multiple tables, such that

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Normalization

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Functional Dependencies & Normalization

Functional Dependencies & Normalization. Souhad M. Daraghma. Redundancy and Normalisation. Redundant Data Can be determined from other data in the database Leads to various problems INSERT anomalies UPDATE anomalies DELETE anomalies. Redundancy and Normalisation. Normalisation

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Chapter 15

Chapter 15. Basics of Functional Dependencies. Lecture # 13 July 19 ,2012. Mid Term Exam Solution Discussion. Chapter 15 Outline. Informal Design Guidelines for Relation Schemas Functional Dependencies Normal Forms Based on Primary Keys

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CS 430 Database Theory

CS 430 Database Theory. Winter 2005 Lecture 7: Designing a Database Logical Level. Logical Design. Define the Relations and Attributes for a Relational Database Key problems: What tables will there be? What columns will each table have? Additional issue:

220 views • 13 slides