Have you ever heard about VoiceXML? It’s a W3C standart that allows you to build web pages that are accessed by voice! It’s very used for services like travel tickets selling, hotel reservation, bank account information and so on. In this post, we’ll give you a general view of how to make a basic hotel reservation
application with VoiceXML and how to run it using Glassfish and MySQL.

First of all, for VoiceXML applications, we need a voice gateway. We used the Voxeo, it’s free and provides you with phone numbers that you can call for free using Skype. All you need to do is create a free account in Voxeo and register your application by informing it’s URL. After registering you’ll receive the unique phone number for your application.

We’ll assume you already know the basics of VoiceXML syntax for the …

My esteemed colleague Giuseppe Maxia dropped me a line to say that my previous example of using "Having", while completely accurate, would probably be slower than a join, especially just for fetching back two items across a large dataset. Well, I'm nothing if up to a bit of fact checking and certainly aggregate functions (such as count) are seen as slower in performance than a join.

The use of "Having" is really intended for a situation where you might have many items you want to match against in such a "many-to-many" table, not necessarily for two items. So I could definitely see Giuseppe being right.

The queries we will pit against each other are below.

In the right corner, the join query aka "The Italian Pasta-bruiser":

SELECT …

We have written before about the importance of using numeric types as keys, but maybe you've inherited a schema that you can't change or have chosen string types as keys for a specific reason. Either way, the character sets used on joined columns can have a significant impact on the performance of your queries.

Take the following example, using the InnoDB storage engine:

PLAIN TEXT SQL:

1. CREATE TABLE `t1` (
2. `char_id` char(6) NOT NULL,
3. `v` varchar(128) NOT NULL,
4. PRIMARY KEY (`char_id`)
5. ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
6.  
7. CREATE TABLE `t2` (
8. `id` int UNSIGNED NOT NULL AUTO_INCREMENT,
…

New Lion Sniper program makes it possible for anyone to become an open source contributor READ MORE

I recently took up a position as an IT and Internet Manager at MobileFun UK.
The position itself is very interesting. The company is very aggressively trying to grow and has lots of new ideas. At the same time, I am stuck with some legacy systems that I need sort out asap. The people here are really very nice. Birmingham is also really nice and far cheaper then London for house prices.


My responsibilities include:

• Maintaining the web servers
• Leading the web development team
• Maintaining all the servers and desktops inside the company - some are quite old.
• Leading the internal application development team
• The databases and the business intelligence of the company - we use MySQL 4 and 5 (I need to upgrade them)
• And.. the phones for the entire company - don't know why.

So I have quite a lot of work to get done and I …

Update to tomorrow's MySQL University session: Petr will start presenting how to use NetBeans for writing PHP. David will continue showing how to use it with MySQL. To set expectations correctly, we've renamed the MySQL University to Working with PHP and MySQL in NetBeans.

Petr Pisl from the NetBeans team will be David Van Couvering's co-presenter for the MySQL University session this Thursday (see the announcement I posted yesterday). While David will focus on NetBeans with MySQL, Petr will demonstrate what NetBeans can do for PHP programmers, a species that uses MySQL all the time. Thanks for joining in, Petr!

In his recent …

I have accepted invitation from David Van Couvering to attend his session and present the PHP features in NetBeans. The session will take place this Thursday, 23rd October and will start at 9:00 Pacific Time (18:00 CET, 17:00 BST). We will use DimDim presentation system so everybody can attend. But  the session has limited capacity of attendees. More info about the session you can find here.

If you are interested, attend the session.

I get a few questions how to set DiskPageBufferMemory.

Before discussing that let's recap a few things:

• Non-indexed attributes (or explicitly defined in CREATE TABLE..) are stored on disk in table spaces.
  
• Indexed attributes are stored in DataMemory
• The hash of the Primary Key is stored in the IndexMemory

Determining how much IndexMemory/DataMemory/Tablespaces that are needed, you can use the dimensioning toolkit.

Now you can setup Undobuffers etc according to my post on disk data a while back.

But what about the DiskPageBufferMemory?! If you have used …

I just came upon a pretty good Hadoop introduction paper posted on Sunâ€s wiki. Apache Hadoop is a free Java software framework that supports data intensive distributed applications. It enables applications to work with thousands of nodes and petabytes of data. Hadoop was inspired by Google's MapReduce and Google File System (GFS) (wikipedia). I wouldnâ€t call it an alternative to mysql – theyâ€re in completely different weight categories. I like …

I think Giuseppe (the man with too many blogs!) was a little too optimistic in his last post… the MySQL Conference Call for Participation has received an amazing amount of proposals, but not enough by our standards.

I personally believe there should be a 1:3 accepted-rejected ratio. Currently, its not there yet. Why do I like such high ratios? It means that there are actually so many good talks, and we (the voting committee) pick the best of the best, to give attendees the most mileage for their time and money. Or am I too harsh?

Anyway, the word on the street is that we will extend the Call for Participation, mostly because it is the right thing to do, and lots of people expect it. Expect an official announcement to go out soon about this. But …