Book Image

Learning Pentaho Data Integration 8 CE - Third Edition

Book Image

Learning Pentaho Data Integration 8 CE - Third Edition

Overview of this book

Pentaho Data Integration(PDI) is an intuitive and graphical environment packed with drag-and-drop design and powerful Extract-Tranform-Load (ETL) capabilities. This book shows and explains the new interactive features of Spoon, the revamped look and feel, and the newest features of the tool including transformations and jobs Executors and the invaluable Metadata Injection capability. We begin with the installation of PDI software and then move on to cover all the key PDI concepts. Each of the chapter introduces new features, enabling you to gradually get practicing with the tool. First, you will learn to do all kind of data manipulation and work with simple plain files. Then, the book teaches you how you can work with relational databases inside PDI. Moreover, you will be given a primer on data warehouse concepts and you will learn how to load data in a data warehouse. During the course of this book, you will be familiarized with its intuitive, graphical and drag-and-drop design environment. By the end of this book, you will learn everything you need to know in order to meet your data manipulation requirements. Besides, your will be given best practices and advises for designing and deploying your projects.
Table of Contents (23 chapters)
Title Page
Credits
About the Author
About the Reviewers
www.PacktPub.com
Customer Feedback
Preface

Understanding and changing the flow of execution


As said in the introduction, a Job must start with a START Job entry. All the entries that follow it are executed in a sequential way, following the direction given by the hops. Also, the execution of the destination Job entry does not begin until the Job entry that precedes it has finished.

Look at the following example:

Job with a simple flow

According to what we just said, we can deduce that:

  1. This Job creates a folder.
  2. After the folder is created, the Job copies some files (most probably to the new folder).
  3. When the files are copied, the jobs executes a Transformation. We can guess that this entry is for operating on the data in those copied files.
  4. Once the Transformation finishes, the Job sends an email.

This is the simplest flow that we can find in a Job. There are, however, several ways in which we can change the flow of execution.

Changing the flow of execution based on conditions

The execution of any Job entry either succeeds or fails. For example...