Showing posts with label FD. Show all posts
Showing posts with label FD. Show all posts
Sunday, April 30, 2023

RELATIONSHIPS AND THE RDM V2 Part 3: SEMANTIC CONSTRAINTS

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Note: This is a multipart re-write of a previous series that, when completed, is intended to replace it. In Part 1 we documented the diffe...
Sunday, April 16, 2023

RELATIONSHIPS & THE RDM V2 PART 2: INTRA-GROUP RELATIONSHIPS

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  Note: This is a multi-part complete re-write of a previous series which, when completed, is intended to replace it. In Part 1 we attribu...
Friday, December 2, 2022

NOBODY UNDERSTANDS FURTHER NORMALIZATION 4 (sms)

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Note: In "Setting Matters Straight" posts I debunk online pronouncements that involve fundamentals which I first post on Linked...
Sunday, October 23, 2022

NOBODY UNDERSTANDS NORMALIZATION 2 (sms)

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Note: In "Setting Matters Straight" posts I debunk online pronouncements that involve fundamentals which I first post on Linked...
Saturday, October 8, 2022

NOBODY UNDERSTANDS NORMALIZATION 1 (sms)

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Note: In "Setting Matters Straight" posts I debunk online pronouncements that involve fundamentals which I first post on Linked...
Monday, September 12, 2022

DATABASE DESIGN: THE STATE OF KNOWLEDGE IN THE INDUSTRY

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Can you identify all the fallacies and misconceptions in the following online exchange ? What is the elephant in the room? Q: “I have done d...
Sunday, August 28, 2022

NOBODY UNDERSTANDS DATABASE DESIGN 1 (sms)

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Note: In "Setting Matters Straight" posts I debunk online pronouncements that involve fundamentals which I first post on Linked...
Sunday, September 19, 2021

TYFK: Calculated Attributes -- Redundancy, Full Normalization and Relational Theory

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Note: Each "Test Your Foundation Knowledge" post presents one or more misconceptions about data fundamentals. To test your knowle...
Tuesday, August 31, 2021

TYFK: Normalized, Fully Normalized, Non-Normalized, Denormalized -- Clearing the Mess

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Note: Each "Test Your Foundation Knowledge" post presents one or more misconceptions about data fundamentals. To test your know...
Thursday, June 10, 2021

RE-WRITE

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See: https://www.dbdebunk.com/2023/08/entities-properties-and-codds-sleight.html
Thursday, August 20, 2020

TYFK: Relations, Tables, Domains and Normalization

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Each " Test Your Foundation Knowledge " post presents one or more misconceptions about data fundamentals. To test your knowledge,...
Monday, July 20, 2020

OBG: Data Independence and "Physical Denormalization"

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Note: I am re-publishing some of the articles and reader exchanges from the old DBDebunk (2000-06). How well do they hold up -- have indus...
Saturday, November 30, 2019

TYFK: 5NF, Association Relations and Join

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Ass ume a conceptual model of a multigroup consisting of two related entity groups, Customers and Orders, where a customer can issue multi...
Sunday, August 25, 2019

Meaning Criteria and Entity Supertype-Subtypes Relationships

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Note: This is a re-write of a previous post. "I have a database for a school ... [with] numerous tables obviously, but consider th...
Friday, May 31, 2019

Normalization and Further Normalization Part 1: Databases Representing ... What?

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Note: This is a re-write of older posts (which now link here), to bring them into line with the McGoveran formalization, re-interpretation...
Sunday, April 28, 2019

Understanding Data Modeling Part 3: OO/UML, and "Graph Data Models"

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In Part 1 we presented some foundation knowledge with which to debunk misconceptions lurking in the industry's "data modeling...
Saturday, April 20, 2019

Understanding Data Modeling Part 2: "E/RM" and "RDM"

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In Part 1 we presented some foundation knowledge with which to debunk misconceptions lurking in the industry's modeling mess that Frie...
Wednesday, January 9, 2019

Data and Meaning Part 3: Database Design

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We have seen in Part 2 that the meaning of data in a database is the conceptual model that the database is intended to represent, namely...
Tuesday, January 1, 2019

Data and Meaning Part 2: Types of Business Rules

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  Per Part 1 , meaning is captured during conceptual modeling as information about objects of interest, specifically their properties (some...
Tuesday, September 18, 2018

Don't Conflate/Confuse Primary Keys, PK Constraints, and Indexes

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“What is the difference between an index and a key? How are they related?” “There seams to be some confusion between what a Primary Key ...