Thursday, 6 October 2011

Normalize you DB

Hi everyone,

In the last couple of days I had the opportunity to normalize a DB. :)

Let me show you a screenshot about a single table:

As you see a lot of data is repeated across the rows. Therefore, I had some bad thoughts about those who let the DB become like this in the beginning. I didn't wanted to do it. As the moments were passing away I let the challenge to excite me. At the end I did it.

Before doing anything the total number of rows in the db was above 100000 and the size of the table was 10,5 MBytes.
My first step was to extract the name of the components into another table and reference them.
This way the size of the table decreased to 8.5 MBytes. And the new table size was 1.5 Mbyte. I earned 0.5 Mbyte, not too much, but the database was much more cleaner.
My second step was to transform the check/change data represented by a string into their numerical representations, this way enabling the database to be internationalized. By doing this the table size decrease to 6.2 MBytes. That means 72% of its original size and the data can be internationalized and we have all the benefits of a normalized DB schema (that means no update problems and a joy to work with).
I also measured the speed of joins operations. Because of the normalization the same data retrieval was increased by 3 times. I put an index onto foreign keys. And the speed was just like before. :)

Design your User Interface

Hello everybody,

I have just finished the book "The Design Of Everyday Things".
It's a great book written by Donald Norman. The guy who wrote "The invisible computer", who worked for the Apple Computer's Advanced Technology Group.

In this book he talks about many-many interesting things:
-The constraints and strength of our short term & long term memory.
-The slips and mistakes our brain makes, while we do things.
-How can we make use of our cultural knowledge and knowledge in the world while design.
-The importance of natural mapping between controls and our actions.
-Interpretation of a system state, and our mental model about the system.
-The (missing) evolution of product line. The evaluation of the already selled products and the importance of debriefing then evolving the product to a better one.

He also describes how primitive were the computers at time of writing.
And he gives us some hints how he imagines the mobile phones should easy our everyday tasks. I had the impression the he was envisioning the nowadays iPhones. He also describes how a graphical user interface would help us to be more effective with the computer interaction. I often had the feeling that he was describing a vision which is very similar about nowadays iPads, iPhones or Microsoft Surface.

I was also symphatizing with him because I remember times when I needed to setup my Mouse and CD driver in the config.sys in order to use those devices. Nowadays everything is much more easier. Especially that, I am a Macintosh user I can spend my time focusing on relevant tasks, without even realizing that I am working.

I finished the book yesterday. After I put the book back onto my shelf I started to browse the new Apple products... They are just amazing. I was especially amazed by the new Siri feature in the iPhone. It remembers me to the "Computer" from Startreak. It is a good example that if we can imagine something then we can sooner or later achieve it. Another feature I imagined even myself and waited a lot is the iCloud. I tried the beta version by downloading Ethics from Aristotle on my Macbook and the book instantly appeared on my iphone too. :) Definetely it enhances our usability experience.

The next day, other news were expecting me. Sad news. The founder and main dreamer, envisioner and technology pioneer Steve Jobs died. So good journey Steve and rest in peace.