Sunday, March 23, 2014

Weekly Update




Note: I usually receive notifications of comments to my posts, which I then publish if they are not spam. Today, however, I noticed a whole bunch of old comments that were waiting for moderation, some of 2013, of which I was not notified. I have just published them and replied. Apologies to the commenters.

1. Quote of the Week
Schemaless describes the storage engine, not the data. Data has schema. No Data is ever Schemaless. Schemaless DBs merely describe a feature of themselves, not the data they store. Namely that they don't store and enforce this schema in addition to the data.
One advantage of this Is that you can change the schema "easily" - helps with up time. Now if you don't evolve the old data with each schema change you can end up with multiple schemas stored in your backend and no way of knowing which data is of which schema without some form of analysis of the data. Show me the Front end that can deal with evolving schemas without knowing about them ;) Point being Schema's always there wether any tier deals with it explicitly or not. Something has to manage it. --LinkedIn.com
2. To Laugh or Cry?
Big data means the reign of the relational database is over
3. Online
What is the best way to explain Normalization 1NF,2NF and 3NF
4. And now for something completely different
Samsung’s entire leadership team is paid less than individual executives at Google, Apple





Tuesday, March 18, 2014

Science, Religion, EAV and the Relational Model




Note: This is a 11/06/17 revision. Thanks to Erwin Smout for his review of a draft and suggesting improvements.

The claims that (1) the relational data model (RDM) is old and, by implication, obsolete -- the industry has purportedly "progressed" -- and (2) promoting it as a superior alternative to NoSQL, Hadoop and other "modern" data management technologies is "religious" in character are routine. They have popped again in a LinkedIn exchange and I responded as I usually do, by asking why is the promotion of a scientific approach deemed religious, while pushing ad-hoc alternatives is not?

Sunday, March 9, 2014

Weekly Update




1. My presentation at SQLSaturday:
The Last NULL in the Coffin: A Relational 2VL Solution to Missing Data
March 15, 2014 11:15am
Microsoft Technology Center, 1065 La Avenida, Building One, Mountain View, CA, 94043
2. Descriptions of all available courses are now posted on the SEMINARS page. Contact me if you are interested in public or private sessions, with possible customization for particular needs.

3. Quote of the Week
1: - a picture is only one representation of a data model: What is the adequate data structure to store a data model: Picture, Text (UML), formal (Gellish), Database) - is there an API to access, create and manipulate data models - do you handle hundreds of types (Entity, Relationship, Attribute): - do you handle one conceptual data model and derived consistent (external) submodels - document : which meta-attributes must be maintained to describe the elements of the data model. How to create different views of the data model (Pictures with different views, detailed printed documents)
2: - How to check the data model with instance data and queries based on the requirements.
3. - Use the ER-Model for Instance data (instead of the relational model) and thereby avoid the impedance mismatch:
4: A query language to access instance data which is based on the Entity-Relationship-Model and NOT on the relational model" --LinkedIn.com
Ugh!

4. To Laugh or Cry?
mysql - additional information on normalization 
5. Online
Do you use Composite Primary Keys to design a good, solid data model?
6. Elsewhere
http://image-store.slidesharecdn.com/a606a81e-9bd4-11e3-8016-22000a9aa8cc-large.png
The database field.

7. And now for something completely different
Zombie Studies Gain Ground on College Campuses








Wednesday, February 26, 2014

Anatomy of a Data Management Project: Distribution Independence



The term "distributed" is thrown around a lot these days. Hype notwithstanding, just as with analytics and data science, distribution in data management is nothing new.In fact, SQL vendors (IBM, Sybase, Ingres, Oracle) -- frequently criticized today for non-scalability -- tackled distribution decades ago. The non-relational systems preceding SQL were not amenable to it, and SQL is the closest to the relational model the industry allows you to get. 

Sunday, February 23, 2014

Thinking Logically: SQL, NoSQL and the Relational Model




I very much doubt that somebody who does not think logically can be a fully competent database professional. From a LinkedIn exchange, an attempt to "address some of my points by calling them out":
JL: You said: "... much of the underlying motivation of NoSQL stuff is anti-relational ..." Okay, so? Data management in graph/document/columnar dbs is not possible because they are "anti-relational"?
The point I made was that, name notwithstanding, NoSQL vendors/proponents are not just anti-SQL, they are actually anti-relational, an important difference.
  • What exactly does this have to do with whether graph/documents/columnar database systems "are possible or not"?
  • Columnar DBMS's can be relational and are not considered NoSQL products.
  • At issue is not the possibility of graph/document systems, but what they are appropriate for.

Sunday, February 16, 2014

Weekly Update




1. Quote of the Week
A view is a logical table based on one or more tables or another view.View can be thought as a virtual table which takes the output of a query and stores it ... A View can be based on a table or another view.--dwhlaureate.blogspot.in

2. To Laugh or Cry?
Will physical modelling and normalization make sense in next decade?

3. Online
Database design patterns

4. Elsewhere

I was reading the following
How Edward Snowden went from loyal NSA contractor to whistleblower
which is interesting in itself, when I came across this:
In mid-2006, Snowden landed a job in IT at the CIA. He was rapidly learning that his exceptional IT skills opened all kinds of interesting government doors. "First off, the degree thing is crap, at least domestically. If you 'really' have 10 years of solid, provable IT experience… you CAN get a very well-paying IT job," he wrote online in July 2006.
Should be familiar to my readers.


5. And now for something completely different  
Who says Congress is not representative?

Martin Kramer is, IMO, possibly, the most astute analyst of the Middle-East: 





Monday, February 10, 2014

"Denormalization for Performance": Don't Blame the Relational Model



 REVISED: 10/18/16

Many common misconceptions are excellent indicators of poor grasp, if any, of  the relational data model (RDM). One of the most entrenched is the notion of "denormalization for performance".

I will not get into the first four of the 5 Claims About SQL, Explained. I do not disagree with the facts, except to point out that the problems are not due the relational nature of SQL and its implementations, quite the opposite: it is due to their poor relational fidelity. I will focus on the fifth, "Should everything be normalized?"

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