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My April post @All Analytics.

Aside from domain constraints, every R-table designed to represent a single class of entities is also subject to table constraints that approximate in the database class business rules in the real world. If the rules are not documented, for the conscientious analyst who wants to guarantee sensible data manipulation and result interpretation they are the next best thing.

Read it All. (Please comment there, not here)



 

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DBDebunk readers should know of David McGoveran (see his bibliography under FUNDAMENTALS), whose work on relational theory and practice has appeared or been discussed on the old site and here over the years. On more than one occasion I mentioned the Principle of Orthogonal Design (POOD) identified by David, who had published several years ago work he did on the subject with Chris Date. The POOD has relevance to updating relations and particularly views and led to Date's VIEW UPDATING AND RELATIONAL THEORY book .

I recently mentioned that David's and Date's understandings on POOD have diverged since their joint effort--currently Date and Darwen reject the POOD as formulated then and David has problems with Date's understanding of it and with their THE THIRD MANIFESTO (TTM) book.

David is working on a book tentatively titled LOGIC FOR SERIOUS DATABASE FOLKS where he will detail his views on RDM in general and POOD and view updating in particular, but in the meantime I asked him to publish an early draft of a chapter on the latter subject, which he did-- Can All Relations Be Updated?--and which he has just revised.

He has asked me to post a clarification on the nature of the differences with Date and Darwen (see next) and I used the opportunity to interview him about his impressive career, which covers much more than database management. David provided written answers to questions.

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1. Quote of the Week

Hopefully with the emergence of better cloud infrastructure and unstructured databases, it'll become easier and easier to build utilities to handle the intake and transformation of big, messy datasets into units of info ready for insights. SocialScale (socialscale.io) just launched an MVP a month ago to provide instant access to raw social data (via Gnip), ready-for-analysis, in any tool. --LinkedIn.com

2. To Laugh or Cry?

Are SQL Relational DBMS's Here to Stay?

3. Online Debunkings

• Comments on Integrity constraints as approximations to business rules
• Comments on First Normal Form, Part 1 Atomicity

4. Interesting Elsewhere

• Lies, Damn Lies And The Myth Of Following The Data
• What Does Big Data Mean: A Cynic's Guide

5. And now for something completely different

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See series starting at

The First Normal Form in Theory and Practice Part I

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1. Quote of the Week

I'm not sure why you think integrity constraints are purely logical. Primary keys are physical constraints. They enforce that the primary key remains unique. Here's an example of SQL that creates a physical foreign key constraint.

ALTER TABLE FactInventoryCollections
 ADD CONSTRAINT
  FK_FactInventoryCollections_ClientPK,
  FOREIGN KEY (ClientPK)
   REFERENCES ViewCubeDimClient(ClientPK);

Physical constraints allow the database engine to return an error if an operation attempts to insert a row that violates any defined constraints. --LinkedIn.com

2. To Laugh or Cry?

When One Data Model Just Won't Do: Polyglot Persistence

3. Online Debunkings

• Comments: Atomicity and its reinterpretation
• Comments: Corporate Data Model re-defined as Enterprise Data Model (EDM)

4. Interesting Elsewhere

David McGoveran has been working on a book tentatively titled LOGIC FOR SERIOUS DATABASE FOLKS intended to set some matters straight regarding the formal, set-theoretic and logic foundations of the RDM which have been misinterpreted. While he is not ready to publish yet, I asked and he agreed to post at his site a draft of a chapter on view updating which I consider a must read (together with the Introduction), particularly since it exposes the thinking behind the Principle of Orthogonal Design rejected by Date and Darwen.

• Introduction
• Can All Relations Be Updated?

David invites comments.


5. New Links

Added the following to the LINKS page:

• The database curmudgeon speaks again
• Synthesizing 3NF Relations from FD's
• KnowOS

6. And now for something completely different

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See  

The First Normal Form in Theory and Practice Part I

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1. Quote of the Week

I have been in the data side of IT for quite some time now and have seen the evolution of how data is ingested, manipulated and regurgitated to the end users in hope of telling our consumers "how much of something did something". The main issue seems to be complexity of the data models and the fact we don't have a model that can expand with the data without adding tons of new schema. The solution.  --LinkedIn.com

2. To Laugh or Cry?

• i have a table with 4 FK's, help me with query to find the tables

3. Online Debunkings

• Comments on The Conceptual-Logical Conflation and the Logical-Physical Confusion
• Comments on 1NF Is Not Structural Regression

4. Interesting Elsewhere

• Knowledge-Based Trust Estimating the Trustworthiness of Web Sources
• Google wants to rank websites based on facts not links

5. And now for something completely different