Tuesday, April 27, 2010

Introduction to MySQL 5.5

In this John Russell's article you can read about speed, scalability, usability of the MySQL database and the InnoDB storage engine.
Read more.


Thursday, April 22, 2010

Pentaho Report Designer and Excel Data Sources - Analyse This

In this tutorial Prashant show us that Pentaho Report Designer (PRD) can be  an alternative to Mircosoft Excel, Access or other big BI vendors.
read it.

Tuesday, April 20, 2010

How to Identify an Apple iPhone, iPod or iPad Visitor to Your Website

Today I report an article where Creg Blucker  with javascript and php examples explains how to catch the visitors of your site using Apple's iPhone, iPod or iPad.

Monday, April 19, 2010

Open Source Reuse Rating Service

Through LinkedIn, I received an email reporting that Antelink has released the Beta version of it's 'Open Source Reuse Rating Service'.
On their blog you can find a summary about this project and a use case based on the Apache Commons libraries.


Saturday, April 10, 2010

Intercept null value on a query

These last days working to create a Pentaho report with openERP data, I came across a serious problem:
if a query return a null value arithmetic operations are in error. The question was how to intercept the null value, surfing on Google I found this
SELECT IFNULL (1,0) this query return 1
SELECT IFNULL(null, 0) this query return 0
Fine my problem was solved NO!!  openERP use postgresql and postgresql doesn't support IFNULL
Again surfing on Google and I found COALESCE
The postgresql manual say:
The COALESCE function returns the first arguments of ITS THAT IS NOT NULL. Returned is null only if all arguments are null. Often it is used to substitute a default value for null values 

Finally my problem was solved my query now  is something like this
SELECT COALESCE(sum(aal.amount * -1) , 0) FROM account_analytic_line AS aal WHERE (aal.account_id=83) and aal.journal_id = 3


Thursday, April 8, 2010

5 Levels of Agile Planning: From Enterprise Product Vision to Team Stand-up

To day I need to suggest a paper that evaluates agile practices when applied in multi-team and multi-person-year projects. Download it here