Book Image

Pentaho Data Integration Quick Start Guide

By : María Carina Roldán
Book Image

Pentaho Data Integration Quick Start Guide

By: María Carina Roldán

Overview of this book

Pentaho Data Integration(PDI) is an intuitive and graphical environment packed with drag and drop design and powerful Extract-Transform-Load (ETL) capabilities. Given its power and flexibility, initial attempts to use the Pentaho Data Integration tool can be difficult or confusing. This book is the ideal solution. This book reduces your learning curve with PDI. It provides the guidance needed to make you productive, covering the main features of Pentaho Data Integration. It demonstrates the interactive features of the graphical designer, and takes you through the main ETL capabilities that the tool offers. By the end of the book, you will be able to use PDI for extracting, transforming, and loading the types of data you encounter on a daily basis.
Table of Contents (15 chapters)

Defining and using Kettle variables

In PDI, you can define and use variables, just as you do when you code in any computer language. We already defined a couple of variables when we created the file in Chapter 1, Getting Started with PDI. Now, we will see where and how to use them.

It's simple: any time you see a dollar sign by the side of a textbox, you can use a variable:

Sample textboxes that allow variables

You can reference a variable by enclosing its name in curly braces, preceded by a dollar sign (for example, ${INPUT_FOLDER}).


A less used notation for a variable is as follows: %%<variable name>%% (for example, %%INPUT_FOLDER%%).

Let's go back to the transformation created in the previous section. Instead of a fixed value for the location of the output file, we will use variables. The following describes how to do it:

  1. Open the transformation (if you had closed it). You can do this from Main Menu or from Main Toolbar.
  2. Double-click on the Text file output step....