Book Image

Pentaho 3.2 Data Integration: Beginner's Guide

Book Image

Pentaho 3.2 Data Integration: Beginner's Guide

Overview of this book

Pentaho Data Integration (a.k.a. Kettle) is a full-featured open source ETL (Extract, Transform, and Load) solution. Although PDI is a feature-rich tool, effectively capturing, manipulating, cleansing, transferring, and loading data can get complicated.This book is full of practical examples that will help you to take advantage of Pentaho Data Integration's graphical, drag-and-drop design environment. You will quickly get started with Pentaho Data Integration by following the step-by-step guidance in this book. The useful tips in this book will encourage you to exploit powerful features of Pentaho Data Integration and perform ETL operations with ease.Starting with the installation of the PDI software, this book will teach you all the key PDI concepts. Each chapter introduces new features, allowing you to gradually get involved with the tool. First, you will learn to work with plain files, and to do all kinds of data manipulation. Then, the book gives you a primer on databases and teaches you how to work with databases inside PDI. Not only that, you'll be given an introduction to data warehouse concepts and you will learn to load data in a data warehouse. After that, you will learn to implement simple and complex processes.Once you've learned all the basics, you will build a simple datamart that will serve to reinforce all the concepts learned through the book.
Table of Contents (27 chapters)
Pentaho 3.2 Data Integration Beginner's Guide
Credits
Foreword
The Kettle Project
About the Author
About the Reviewers
Preface
Index

Chapter 9


loading slowly changing dimensions

1

(a). The decision for the kind of dimension is not related to data you have. You just have to know your business, so the last option is out. You don't need to keep history for the name of the film. If the name changes it is because it was misspelled, or because you want to change the name to upper case, or something like that. It doesn't have sense to keep the old value. So you create a Type I SCD.

2

(c). You can use any of these steps for loading a Type I SCD. In the tutorial for loading a type I SCD you used a Combination L/U, but you could have used the other too, as explained above.

loading type III slowly changing dimensions

1

(b). With a Database lookup to get the current value stored in the dimension. If there is no data in the dimension table, the lookup fails and returns null; that is not a problem. After that, you compare the found data with the new one and set the proper values for the dimension columns. Then you load the dimension either with a Combination L/U or with a Dimension lookup, just as you do for a regular Type I SCD.