Saturday, May 20, 2017

This Week

1. Database Truth of the Week

"If the physical model does not preserve the properties of the logical model, then it is—by definition—incorrect. That is why the physical model must be derived from the logical model, not the other way around." --David McGoveran

2. What's Wrong With This Database Picture?

"If we step back and look at what RDBMS is, we’ll no doubt be able to conclude that, as its name suggests (i.e. Relational Database Management System), it is a system that specializes in managing the data in a relational fashion. Nothing more. Folks, it’s important to keep in mind that it manages the data, not the MEANING of the data! And if you really need a parallel, RDBMS is much more akin to a word processor than to an operating system. A word processor (such as the much maligned MS Word, or a much nicer WordPress, for example) specializes in managing words. It does not specialize in managing the meaning of the words ... So who is then responsible for managing the meaning of the words? It’s the author, who else? Why should we tolerate RDBMS opinions on our data? We’re the masters, RDBMS is the servant, it should shut up and serve. End of discussion." --Alex Bunardzic, Should Database Manage The Meaning? 

3. To Laugh or Cry?

"If trust and robustness aren’t an issue, there’s nothing a blockchain can do that a regular database cannot." --Four key differences between blockchains and regular databases

4. Publications

The first paper in the new UNDERSTANDING OF THE REAL RDM series, Interpretation and Representation of Database Relations is available for ordering here.



5. Oldies but Goodies

The database curmudgeon speaks again

6. Of Interest

And Now for Something Completely Different   


This week @The PostWest: Evidence of the Demise of America and Western Civilization


The Data Driven 1984: Between corporations, the government and hackers the public is fucked.

This Week's Must Reads (to be read jointly)

The Technology Dystopia

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


  1. There is nothing wrong with that picture except perhaps that it was malignantly misconstrued as an argument against data constraints enforced by the DBMS. DBMS's enforcing declared data constraints are not "DBMS opinions on the data", they are user opinions on the data. And the DBMS enforcing such a constraint is just the DBMS expecting the users to abide by their own opinions.

  2. I think your papers make clear that what is wrong here is that while the DBMS is not responsible for managing the semantics as described by the informal conceptual model, it *can be* and *should be* responsible for, as much as possible, ensuring the data maintained by the DBMS is consistent with those semantics via the formalization of the conceptual model at the logical level. As your previous post pointed out, SQL DBMS' don't provide much in the way of tooling to accomplish this. In this I agree with Erwin's comment.

    As an aside, the example of the word processor cuts both ways. A good word processor also, as much as it can, attempts to ensure the words input to it are as consistent with the writer's intent as much as possible. The constraints it imposes are spell check and grammar check. While abiding by them is optional, the result of not abiding by them is a document of poor quality.


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