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June 20, 2012

The NULL Logic In The SQL

On today's course "Anatomy Of Database" by Targo Tennisberg among other things I have learned very simple thing about NULL in SQL:

I've always thought that NULL means nothing, but actually it means unknown.

And that is why we can not compare some value with NULL - we can not use expressions like value = NULL or value > NULL, because it basically means that we are askind "does value equals to unknown?" It is impossible to answer that question. So we need to use expression value IS NULL, which means "does value is unknown?" Yes, it can be unknown.

The thing that impresses me - that I've always knew, that I should use IS NULL, not = NULL, but I've never thought why (when I started to use PL/SQL Developer, for the first time I wrote = NULL in the querry).

June 19, 2012

The Audience Is Important As The Presenter

Today I participated in the course "Security And Unit Testing" by Erki Männiste. And the thing is, that I have been participated in it for the second time: first time the audience was the testing team, second time - developing team. The course and presentetion were the same, but for now on I decided to participate only with developers, if it is possible.

Reason number 1: usually the one target group, are they testers or developers, asks the same questions. If I am tester, so I can ask 90% of the questions, that will be performed in the testers' audience and that are interresting and useful for me. So being in the developers' audience I can ask testers' questions and hear developers' - kill two birds with one stone.

Reason number 2: if the course is about testing area, that means, that developers asks questions from the nontester position - I can see, how nontesters understand the topic, which gives me wide-angle overview about it and helps to delve into it.

Reason number 3: type of developers' questions helps me to imporove the comunication with them. I can understand their logic and see problems, that they are interesting in.

Unreason: there is 10% (subjective evaluation) of the questions in the testers' audience, that can encrease my testing experience. Especially they are likely to be asked if there is presenting a really good test master in the audience.

But, in most cases, the same course with the developers is much more useful, than the same course with testers.

And here is Erki Männiste - QA specialist at Nortal - presenting this course for the testers' audience and showing some example:

June 4, 2012

Stopwatch Browser Extension

Application that I am testing is working with a data from the cache, so there is automated cache update every minute or two. So, it is happening that I need a stopwatch, to know the moment, when the cache is surely updated. And so I need a stopwatch tool.

At the beginning I used a stopwatch in the mobile phone (Android has it by default). It is very easy and nicely to use it, because I can see the time anytime - there is no need to open a new window or a new tab to see it. But there is one disadvantage - the smartphone battery is dischargin very fast if I use stopwatch 2 or even 1 hour. So I decided to find a browser stopwatch extension.

I had only 3 requirements:
  • the time should be seen in the icon (I don't want to open a tab or a popup window to watch the time);
  • the start/stop/reset functions should be available by one click (I don't want to open some popup window first and only then to click some start button)
  • the tool should be able to run in the background (I want to change windows and tabs during the calculations).

So I started to search the extension.

Firefox
I have found such extension for Firefox really quickly - it is Autotimer. Not very simple tool, but very convinient - I can see the time in the status bar and I can operate start/stop/reset with only one/two mouse clicks - perfect tool! And there are good manuals about this tool on the web page.

Chrome
Then I started to find such extension for Chrome – it is disaster! There is not even close such tool. Here is a table with tools and brief discriptions. First surprise was that not all stopwatches converts seconds to minutes - some of them show 100 instead of 1:40 - that is not acceptable for me.

Table agenda:
Icon - does tool shows time on the icon;
Click - does functions start/stop/reset are available by one mouse click;
Back - does stopwatch runs in the background;
Mins - does tool converts seconds into minutes (shows 1:40 instead of 100);
Info - additional information about the tool.

Tool Icon Click Back Mins Info
Quickrr Stopwatch & Countdown No No Yes Yes
Stop Watch & Timer Toolbox No No Yes Yes
Stopwatch No No No Yes
Stopwatch Tab Yes Yes Yes Yes Different times for every tab.
Online Stopwatch No No No Yes Does not work.
Countdown Yes No Yes No After 1 minute shows only minutes.
Quickrr Productivity Kit No No Yes Yes
CountDown Yes No Yes No
Stopwatch No No No Yes
StopWatch No No No Yes
Stopwatch No No No Yes
Clock No No No Yes

As you can see, there is only one extension that has all yes's - Stopwatch Tab. And there is a comment - different times for every tab, which actually means, that it shows time not on the icon but in the tab header:


Which is actually very good, because that means, that the time (of the active tab) is seen in the taskbar as well:


And the time in the tab header does not disappear when I am moving through some links in the tab - I can open what ever I want and the time is still calculating in the tab header.

So, the best Chrome stopwatch extension for me and at this time is the Stopwatch Tab.