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The 80/20 Rule

domingo, 16 octubre 2016 21:00
antoniomartel
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How can we avoid featuritis and concentrate just on the tasks that will make us more efficient? Many years ago, approximately a century ago, someone called Pareto realised that 20% of the pea pods in his garden amounted for 80% of his crop. The remaining 80% of his pea pods amounted to the other 20% of his pea crop. Intrigued by this ratio, he also checked that he could use this rule to other fields. He went on to discover that, back then, 20% of the population had 80% of the income. The remaining 20% of the wealth was in the hands of the poorest 80% of the population. This principle, based in empirical knowledge, has been in use since then. It helps improve efficiency and productivity in economics, commercial distribution, marketing, engineering, and, naturally, in software development.
For example, we start to develop our product with a huge list of requirements and features as a base. Yet we know that only 20% of those features will be used 80% of the time. A large chunk of the remaining features will only be used 20% of the time. We can apply this principle to development time. Using it, we can deduce that if it takes us about 10 months to build a product, in 2 of those months we will be able to develop 80% of the features. Thus it would take us about 8 months to solve the remaining 20% of the most complex and difficult features. This leads us to ponder: will people use these features? Are they really indispensable?

Say we manage to identify the most important features, and we keep them as simple as we can. Wouldn’t we be able to dispense with 8 months of work and deliver a highly effective product in 2 months only? We already know that 20% of our effort will produce 80% of our results. Wouldn’t it be worthwhile to sit for a moment and think for a bit about what we should devote our time to? I’m sure it would.

You can find texts like this and many other about how to manage agile projects in my book Agile 101: Practical Project Management (available on Amazon).

Book on Scrum: Agile 101, Practical Project Management
Agile 101 – Practical Project Management

Translation by Begoña Martínez. You can also find her on her LinkedIn profile. Proofreading by David Nesbitt.

Keep it Simple from Agile 101 book

domingo, 09 octubre 2016 22:00
antoniomartel
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Some time ago, I had a conversation with an IT colleague, about the sector nowadays. Something reminded me of an Andrés Diplotti cartoon I’d seen on Google+. In it you could see a client reviewing the application that the programmer had delivered. The client says : “It’s all fine, but I don’t see a Cancel button”. The programmer replies: “I don’t program for cowards who cancel at the last minute.”
I’ve been a programmer for a long time. I’m still a programmer, in part. So I can recognize this kind of arrogance (maybe not to that extent). I suppose that it’s a sin of my youth, a brashness that’s been mellowing with age and that some of us already felt in college.
Back then I had just discovered software-design patterns in the book The Gang of Four. Our applications started to be filled with design patterns, the more the better. It looked like we were in some sort of contest. We had to see who used the most obscure, complex pattern —the one that would be the hardest to understand. With this in mind, I can understand the posts and articles I read now. They discuss refactoring old code to get rid of design patterns, and about how expensive it is for some projects.
As the years have gone by, I have suffered the KISS principle (Keep it Simple, Stupid) in my own flesh.  Not just with patterns, but also with the customization of on-screen graphic components. Or with “phantom requirements.” This is a term I once heard from a fellow worker. It refers to those features that no one has requested, but that you consider important for your clients. Things that “most probably” they’ll end up needing. It’s the malady known as featuritis. It makes us think that the more features or characteristics our app has, the more valuable the client will find it.
A long time ago, a client’s project manager commented that someone on another work team had told him that a feature he wanted was impossible. I told him that practically everything can be done, provided enough time is spent on it. I wasn’t clear enough. I should have added: but is it reasonable to use all that time for that feature? You can use practically any programming language to send a rocket to the Moon. But, do you really want to go to the Moon, or do you want a finished app by the deadline?
So, you are saying that my design is too complex?


You can find texts like this and many other about how to manage agile projects in my book Agile 101: Practical Project Management (available on Amazon).

Book on Scrum: Agile 101, Practical Project Management
Agile 101 – Practical Project Management

Translation by Begoña Martínez. You can also find her on her LinkedIn profile. Proofreading by David Nesbitt.

Agile 101 available for pre order

lunes, 03 octubre 2016 22:07
antoniomartel
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New ebook, Agile 101, is already available for pre order in Kindle stores worldwide. You can find the link to the Amazon.com page here: Agile 101 – Practical Project Management. Order it now and you’ll receive your copy on 5th of November when it will be finally released.

You don’t need a Kindle device to read it, all it takes it’s to download a Kindle reader app for PC, Mac or Android from Free Kindle reading apps or just start reading in any device typing read.amazon.com in your web browser.

It is the English version of the 3rd edition of Gestión práctica de proyectos con Scrum (Spanish edition) which reached twice number 1 in sales at Amazon Spain (across all genres), and remained in the Top 100 for five consecutive days.

With Agile 101 you’ll learn:

  • The main advantages and disadvantages when implementing Scrum. The things you should bear in mind and those you should avoid.
  • How to make agile estimates.
  • How to handle the project’s budget while allowing your client to modify the required functionality.
  • The lessons I have learned during my years as a software development professional. I will tell you what I did right but also what I did wrong, so that at least you don’t make the same mistakes I did.
  • Tips and tricks to prepare for the Professional Scrum Master certification (PSM I), so you improve your chances of landing better jobs.
Begoña Martínez translated the book into English. You can also find her on her LinkedIn profile. David Nesbitt proofread the translation.
Cover and back cover of the new edition have been designed by Alex Caja Almonacid (also cover and back covers of Spanish editions of Gestión práctica de proyectos con Scrum and Certificación Professional Scrum Master – PSM I).

Agile 101 – Practical Project Management

Oracle XE, Forms 6i y un viaje a Ecuador

miércoles, 28 septiembre 2016 19:00
antoniomartel
2 Comentarios

Hace algún tiempo tuve que realizar una implantación de una aplicación desarrollada en Oracle Developer 6i (Forms y Reports) para un museo. Por razones económicas decidimos utilizar una licencia Oracle Express Edition 10g, pero al intentar arrancar la aplicación accedíamos a ver durante un instante la consola de Windows y se cerraba inmediatamente.

El proyecto se estaba pasando de las horas estimadas para resolverlo y ahora teníamos un problema con el que nadie en la empresa se había topado antes. Consultamos la página metalink de Oracle, foros y páginas sobre desarrollo con Oracle.

Finalmente, tras muchas búsquedas en Google obtuvimos la respuesta al problema en el foro de Oracle Users Group de Ecuador, exactamente en una entrada de Paola Pullas y los comentarios al mismo.

Parece ser que Oracle XE 10g necesita de un parche para funcionar con Developer 6i y además cambiar el juego de caracteres a UTF8. Les indico aquí los pasos que tuvimos que realizar.

Primero, pedirle al DBA responsable de la instalación de la base de se conectara a la base de datos XE como SYSDBA en el sqlplus y ejecutara las siguientes instrucciones para cambiar el juego de caracteres.

SHUTDOWN IMMEDIATE;
STARTUP MOUNT;
ALTER SYSTEM ENABLE RESTRICTED SESSION;
ALTER SYSTEM SET JOB_QUEUE_PROCESSES=0;
ALTER SYSTEM SET AQ_TM_PROCESSES=0;
ALTER DATABASE OPEN;
ALTER DATABASE CHARACTER SET INTERNAL_USE UTF8;
SHUTDOWN;
STARTUP RESTRICT;
SHUTDOWN;
STARTUP;

Posteriormente fue necesario ejecutar el siguiente parche de Oracle sobre la instalación de Oracle Developer: Parche 18 de Developer, Patch number 4948577.

Espero que esta entrada resuelva el problema a algún desarrollador. Seguro que aún quedan sistemas y aplicaciones que están usando esta configuración.

Totales en blanco en Oracle BI Discoverer

martes, 27 septiembre 2016 19:20
antoniomartel
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Otro post técnico. En este caso cómo resolver el problema de los totales en blanco en Oracle Business Intelligence Discoverer:

En algún trabajé como administrador de la EUL (capa de usuario final) con las herramientas de Discoverer y nos encontramos con un problema que nos trajo de cabeza durante unos días: Los totales de algunas columnas se mostraban en blanco a pesar de contener datos y solamente mostraban una cantidad cuando sumaban sólo un registro. Si había más se mostraban vacíos.


Es algo que aparentemente puede parecer un error o bug de esta herramienta pero resultó ser una decisión de diseño en la herramienta. Me explico:

Si tenemos dos carpetas relacionadas entre sí como maestro-detalle y en la carpeta maestra tenemos la cantidad o el número que vamos a sumar, tendremos un problema ya que la suma contará la cantidad del registro maestro tantas veces como elementos haya en el detalle, y probablemente no es esto lo que queremos.

Mejor verlo con un ejemplo. Si tenemos una carpeta maestra con los datos de guías turísticos en la que además indicamos cuál es la tarifa que cobra cada guía mensualmente:

Id.     Nombre Tarifa
1         Antonio    2000€
2        Juan          1000€
3        Marta        1500€

Si además tenemos una carpeta detalle en la que tenemos la relación de idiomas que habla cada guía, tendremos algo como esto:

Id.     Nombre     Tarifa Idioma
1         Antonio        2000€        Inglés
2         Juan              1000€        Inglés
2         Juan              1000€       Alemán
2         Juan              1000€       Sueco
3         Marta            1500€       Alemán

Si hacemos un ‘Summary‘ o ‘Total‘, la herramienta de Discoverer nos mostrará que Antonio cobra 2000€ al mes, Marta 1500€ y que Juan cobra «_____». Es decir nos mostrará la casilla en blanco o vacía. Si mostrase un resultado nos daría 3000€, cantidad que no es la que realmente cobra Juan.

Tenemos algunas formas de resolver esto:

  1. Quizás la cantidad que estás sumando no deba ir en la carpeta detalle. Deberías revisar el diseño de la base de datos.
  2. Quizás la relación entre ambas carpeta deba ser de 1 a 1 y lo tienes puesto por error de 1 a muchos.
  3. Si todo lo anterior está correcto, hay una cosa más que puedes hacer: Decirle a Discoverer que sume la cantidad de todas formas, aquí están los pasos:
    1. Activar en las opciones del Discoverer Desktop la casilla ‘Show the sum of the values displayed in the contributing cells‘
    2. Establecer con valor 1 en lugar de 0 las propiedades AllowAggregationOverRepeatedValues yAggregationBehavior del fichero prefs.txt en el servidor de Discoverer en la ruta $ORACLE_HOMEDiscovererutil

Este último caso debemos tomarlo siendo conscientes de lo que supone. Aunque sea perfectamente válido para el caso que estás intentado resolver es posible que en otro informe que en el futuro esté colgado del mismo servidor, impidamos ver al administrador que hay un problema (fan trap) y se muestren totales con importes erróneos como el de la tarifa de Juan.