Test your knowledge of MySQL! There are four sets of questions covering the four MySQL Certifications.

These questions are closely modeled on actual questions from the Associate, Developer, DBA, and Cluster DBA exams.

These questions are for entertainment purposes only. And hopefully those of you lacking your MySQL Certifications will entertain taking the exams!

Sergey Petrunia brought to my attention the work Optimizer Team has done in MySQL 6.0 related to SubQuery Optimization.

I am excited to see this information published honestly outlining the things which are fixed now and things which are still not handled well. According to the bug sampling done by Optimizer Team 68% of reported issues are fixed (significantly improved) by changes in MySQL 6.0 which is far from all the issues but still very good number.

If you had issues with subqueries in MySQL 4.1 or 5.0 and pulled away from using them I'd encourage you to try MySQL 6.0 and see if your issues are fixed or described in the documentation published. If not report the bug and let optimizer team to know how you're suffering

In particular you can review Currently Working …

Many MySQL users like to use the MySQL monitor. The MySQL monitor is the executable bin/mysql (or if you are on MS Windows, bin\mysql.exe) and is perhaps better known as the MySQL command-line tool or MySQL command-line client.The MySQL monitorBasically, the MySQL monitor is a standard, text-based terminal that connects to a running MySQL Server when it is started. Once the connection is established, the user can enter text via the computer keyboard, which is at some point sent to the server. The server attempts to interpret the received text as SQL, which is then executed, sending the result back to the MySQL monitor. The MySQL monitor then prints the received results on the screen:

mysql> SELECT COUNT(*) FROM world.City;
+----------+
| …

We have just published an interview with our CEO Mårten Mickos on our Developer Zone, where he answers a number of questions from the Community Team about Sun's plans to acquire MySQL AB and what this means for the MySQL User Community and the direction of the product (thanks to Colin for compiling and editing the text). I hope that the comments help to calm the concerns of some people about the future of MySQL with regards to Open Source, support of platforms or language bindings:

CT: Is MySQL fully committed to free and open source software, and the GPL?
Mårten: Yes.
CT: What does the Sun acquisition mean for Linux support? What about Windows, Mac OS/X and other platforms?
Mårten: One of the reasons …

This TOTD (Tip Of The Day) shows how to install Rails 2.0.x in JRuby 1.0.3 and JRuby 1.1 RC1. Then it describes how a simple Rails application can be created and deployed using WEBrick.

First, lets deal with installing Rails 2.0.x in JRuby 1.0.3 and JRuby 1.1 RC1.

Step 1: How to install Rails 2.0.x in JRuby 1.0.3 ?

• Download and Unzip JRuby 1.0.3. This creates "jruby-1.0.3" directory.
• Install Rails by giving the following command in the newly created directory:
  
  bin/jruby -S gem install rails --include-dependencies --no-ri --no-rdoc
Bulk updating Gem source index for: http://gems.rubyforge.org
Successfully installed rails-2.0.2
Successfully installed activesupport-2.0.2
Successfully installed activerecord-2.0.2
…

A

"Defensive patents" make as much sense as leaving a loaded gun around the house. Like a home robbery, it is more likely it will be used against the home owner then the intruder.

If you have an idea, publish it to establish prior art. Patent trolls come from patent houses that produce no products. This means that they
cannot be counter sued. The fallacy with defensive patents is assuming you will ever use it as a weapon.

What should you really fear? The company you work for changes direction or goes under. It then sells the patent, and the patent ends up in the hands of a patent house.

Trust the people you know running your company?

If you do not, you should be finding a different employer.

But what about the next guy?

You can never know.

The solution is to establish prior art. Defensive patenting just continues the cycle of software …

How often do we think about our http sessions implementation? I mean, do you know, how your currently used sessions-related code will behave when sessions number in your database will grow up to millions (or, even, hundreds of millions) of records? This is one of the things we do not think about. But if you’ll think about it, you’ll notice, that 99% of your session-related operations are read-only and 99% of your sessions writes are not needed. Almost all your sessions table records have the same information: session_id and serialized empty session in the data field.

Looking at this sessions-related situation we have created really simple (and, at the same time, really useful for large Rails projects) plugin, which replaces ActiveRecord-based session store and makes sessions much more effective. Below you can find some information about implementation details and decisions we’ve made in this plugin, but if you just want to try it, then …

We got a chance to speak with Mårten Mickos, CEO of MySQL AB, about Sun's planned acquisition of MySQL, and we asked him some questions, that the community at large, might have.