Book Image

Pentaho Data Integration Beginner's Guide - Second Edition - Second Edition

By : María Carina Roldán
Book Image

Pentaho Data Integration Beginner's Guide - Second Edition - Second Edition

By: María Carina Roldán

Overview of this book

Capturing, manipulating, cleansing, transferring, and loading data effectively are the prime requirements in every IT organization. Achieving these tasks require people devoted to developing extensive software programs, or investing in ETL or data integration tools that can simplify this work. Pentaho Data Integration is a full-featured open source ETL solution that allows you to meet these requirements. Pentaho Data Integration has an intuitive, graphical, drag-and-drop design environment and its ETL capabilities are powerful. However, getting started with Pentaho Data Integration can be difficult or confusing. "Pentaho Data Integration Beginner's Guide - Second Edition" provides the guidance needed to overcome that difficulty, covering all the possible key features of Pentaho Data Integration. "Pentaho Data Integration Beginner's Guide - Second Edition" starts with the installation of Pentaho Data Integration software and then moves on to cover all the key Pentaho Data Integration concepts. Each chapter introduces new features, allowing you to gradually get involved with the tool. First, you will learn to do all kinds of data manipulation and work with plain files. Then, the book gives you a primer on databases and teaches you how to work with databases inside Pentaho Data Integration. Moreover, you will be introduced to data warehouse concepts and you will learn how to load data in a data warehouse. After that, you will learn to implement simple and complex processes. Finally, you will have the opportunity of applying and reinforcing all the learned concepts through the implementation of a simple datamart. With "Pentaho Data Integration Beginner's Guide - Second Edition", you will learn everything you need to know in order to meet your data manipulation requirements.
Table of Contents (26 chapters)
Pentaho Data Integration Beginner's Guide
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Best Practices
Index

Time for action – generating custom files by executing a transformation for every input row


Suppose that 75 is the threshold below which a student must retake the examination. Let's find out the list of students with at least one score below 75, that is, those who didn't succeed. Then, let's create one file per student telling him/her about this.

If you did the previous sections successfully, you should know that you already have half the work done! The prepare_data.ktr transformation builds the list of students. If not, before proceeding, please go back and create that transformation; you will need it now.

  1. Create a new transformation.

  2. Drag to the canvas a Get rows from result step.

  3. Double-click on the Get rows from result step and use it to define two string fields: a field named student_code and another field named student_name.

  4. Add a User Defined Java Expression step and create a hop from the Get rows from result step to this new step.

  5. Double-click on the step and configure it as shown:

  6. After...