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THE DBDEBUNK GUIDE TO MISCONCEPTIONS OF DATA FUNDAMENTALS available to order here.



1. What's wrong with this picture?

"Our terminology is broken beyond repair. [Let me] point out some problems with Date's use of terminology, specifically in two cases:

1. "type" = "domain": I fully understand why one might equate "type" and "domain", but ... in today's programming practice, "type" and "domain" are quite different. The word "type" is largely tied to system-level (or "physical"-level) definitions of data, while a "domain" is thought of as an abstract set of acceptable values.
2. "class" != "relvar": In simple terms, the word "class" applies to a collection of values allowed by a predicate, regardless of whether such a collection could actually exist. Every set has a corresponding class, although a class may have no corresponding set ... in mathematical logic, a "relation" *is* a "class" (and trivially also a "set"), which contributes to confusion.

In modern programming parlance "class" is generally distinguished from "type" *only* in that "type" refers to "primitive" (system-defined) data definitions while "class" refers to higher-level (user-defined) data definitions. This distinction is almost arbitrary, and in some contexts, "type" and "class" are actually synonymous." --Comment @dbdebunk.com

2. Quote of the Week

"Physical models depend on the storage mechanisms being targeted. For SQL DBMSs, I would focus on tables and the associated integrity mechanisms ... The basic difference between an ER model and a relational model is that an ER model distinguishes value sets from entity sets. Mapping between entity sets gives us relationship sets and mapping from entity or relationship sets to value sets gives us attributes ... Thus, if a physical model is designed to implement a logical model, there are no such things as "entity records", only physical representations of relations which, denormalized for practical reasons, may superficially resemble structured entities." --LinkedIn.com

3. To Laugh or Cry?

• Data Model for the US Presidential Transition 2017
• Outpan - The Database of Everything

4. Online debunkings

See my comment on independence and triggers

5. Of Interest

• Advanced Data Structures
• How We Knew It Was Time to Leave the Cloud

And now for something completely different

The PostWest (The future of the West is all behind it)
 
The best thing you can do to really understand the Israeli-Palestinian Conflict, Islam and the Middle East and the Western never-ending utter failure to deal with that is to read Martin Kramer.

• Martin Kramer's Scholarly Views on Israel, Islam and the Middle East (REVIEW)
• Martin Kramer Knows Why America Keeps Mucking Up The Middle East
• Setting the Record Straight on Israel
• The Growing Gap Between Israel And American Jews (Scroll down to Martin Kramer's contribution)

Article of the week

Counter-Error: Separating Fact from Fiction in the Middle East

Videos of the week

• Martin Kramer launches The War on Error Israel, Islam, and the Middle East
• ASMEA 2016 Keynote Address

Pinch-me of the week

Lebanon's new president vows to 'protect' country from ... Israel!

Book of the week (Purchase via this link to support the site)

Kramer, M., THE WAR ON ERROR

Note: I will not publish anonymous comments. If you want to say something, stand behind it. Otherwise don't bother, it'll be ignored.