Book Image

QlikView for Developers

By : Miguel Angel Garcia, Barry Harmsen
Book Image

QlikView for Developers

By: Miguel Angel Garcia, Barry Harmsen

Overview of this book

QlikView is one of the most flexible and powerful Business Intelligence platforms around. If you want to build data into your organization, build it around QlikView. Don't get caught in the gap between data and knowledge – find out how QlikView can help you unlock insights and data potential with ease. Whether you're new to QlikView or want to get up to speed with the features and functionality of QlikView, this book starts at a basic level and delves more deeply to demonstrate how to make QlikView work for you, and make it meet the needs of your organization. Using a real-world use-case to highlight the extensive impact of effective business analytics, this book might well be your silver bullet for success. A superb hands-on guide to get you started by exploring the fundamentals of QlikView before learning how to successfully implement it, technically and strategically. You'll learn valuable tips, tricks, and insightful information on loading different types of data into QlikView, and how to model it effectively. You will also learn how to write useful scripts for QlikView to handle potentially complex data transformations in a way that is simple and elegant. From ensuring consistency and clarity in your data models, to techniques for managing expressions using variables, this book makes sure that your QlikView projects are organized in a way that's most productive for you and key stakeholders.
Table of Contents (24 chapters)
QlikView for Developers
Credits
About the Authors
Acknowledgements
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
Index

QVD and QVX files


We have now gone through the process of loading data from traditional databases and simple table files. In this section, we will take a deeper look at the QVD and QVX file types, which are used by QlikView to store and read data in an optimized format. We will talk a little more about both of these types, and the benefits and uses of each of them.

QVD files

QlikView Data (QVD) files are used to extract and store data into and from QlikView. This means that whichever table you read from whichever database, you can store it in the QVD format before or after any transformations you perform on the table. The special characteristics of this file type are:

  • It contains only one logical table.

  • It uses a special algorithm to compress the data, achieving compression rates of up to 90 percent, depending on the fields' cardinality of the underlying data.

  • When reading a QVD table file in QlikView, the loading speed is anywhere from 10 to 100 times faster than when loading from a database...