Friday, August 15, 2014

Weekly Update

1. Quote of the Week
Invoice number is the key (key is not unique in this table). Although structure or key constraints doesn't enforce uniqueness of rows, the assumption is there will not be duplicate rows.

2. To Laugh or Cry?
Relational Queries by Reference

3. Online Debunkings
What is Weak Subtype

5. And now for something completely different
Tim's Vermeer

@The PostWest

Sunday, August 10, 2014

The 'Real World' and Database Design

Conveying data fundamentals to practitioners, losing neither rigor, nor the audience is a difficult task. There are many experienced professionals with tool expertise, but poor foundation knowledge for which there is little regard. Even in academia education has been substituted by training, which is not the same thing.

One dilemma faced by an educator is the tension between the simplicity of examples effective for conveying general concepts or principles and the complexity of the reality to be represented in databases. The latter requires integration of many concepts and principles, as well as thorough business knowledge. This is part of the reason why I normally refrain from specific online modeling/design advice and limit myself to the general principles that must be adhered to in the process.

Sunday, July 27, 2014

UPDATED: Weekly Update

1. Quote of the Week
Q: In a nutshell, what does RDF based Linked Data facilitate?
A: The ability to find and describe stuff using attributes (relations, properties, features, fields, characteristics).

2. To Laugh or Cry?
Data Model now offers Relationship Modeling

3. Online Debunking
Data Vaults - Why Or Why Not

4. Elsewhere
5. And now for something completely different

In its decline, theWest is becoming impotent and increasingly irrelevant in world affairs e.g. Russia, Syria, Iraq, Afghanistan, China, Libya, you name it. It is taking hypocritically its frustration on Israel and the Jews--its classic scapegoating during crises--reinforced by fear from internal Islam.

I am restarting my PostWest blog and will link regularly to posts in this section.

Critical comments that
  • fail to show my facts to be false; or, if they are true, that my conclusions do not follow;
  • are posted anonymously
will not be published and addressed.

Sunday, July 13, 2014

Data Model: Neither Conceptual, Nor Logical, Nor Physical

Chris Date once titled an article Models, Models Everywhere, Nor Any Time to Think and I wrote about A Model to Call One's Own. We referred to the continuous proliferation of new "models" at the expense of mastering the fundamental and sound ones we have and the vagueness, confusion, misuse and abuse of the term 'model' (see, for example, Canonical data model implicitly managed through Enterprise Data Modeling). That is why, more than four decades after the concept of data model was introduced by Codd, we still have questions like:
Q: I understand that the database design process occurs in the following sequence:
Conceptual Data Model -> Logical Data Model -> Physical Data Model
Can someone please clarify how the relational model applies to this process?
Can you?

Sunday, July 6, 2014

Weekly Update

1. Quote of the Week
Don't confuse Data(base) Modeling with Business Modeling. All DBA are correct when they are talking about Database Modeling. If you want to ensure unique record on Business level, just add a unique composite index. (not as Key). But far to often, a unique record on business level is not ALWAYS unique (only most of the time)

2. To Laugh or Cry?
Create database vs schema

3. Online Debunkings

4. Interesting Elsewhere

5. And now for something completely different
 And if you like what they're doing to San Francisco, you'll love what they'll do to other cities:
Google Exec Rises Ire in Portland
 Symptoms of societal malaise.