Book Image

QlikView 11 for Developers

Book Image

QlikView 11 for Developers

Overview of this book

Business Intelligence technologies are a must-have in every business to make informed decisions and keep up-to speed with the ever-evolving markets. QlikView's disruptive technology makes it a key player and leader in the industry; with its flexibility and powerful analytics environment, building QlikView apps can be mastered by both, business users as well as developers. This book will help you learn QlikView Development from a basic to a practitioner level using a step-by-step approach in a practical environment, and apply proven best practices on each topic. Throughout the book, we will build a QlikView app based on real data about Airline Operations that will help "HighCloud Airlines" make informed business decisions and analysis-guided strategies. HighCloud Airlines executives are evaluating if entering the US market is a good strategy and, if so, which line of business should they focus their investments on; they need QlikView to make the best decision. The application will be evolving chapter by chapter, along with your skills, going from a simple proof of concept to creating a Data Model, adding a custom style, building a Dashboard and handling and manipulating the source data via script. We will meet the "HighCloud Airlines" requirement by using many different data visualization objects and time-saving techniques. The whole application uses real data taken from the Bureau of Transportations statistics of the US and encompasses the operations of Airlines both domestic and international. With three years worth of data, you will help HighCloud Airlines discover where people travel the most, which are the Carriers with the most market share, what is the average load factor per airline, which aircraft is the most used to perform flights, which are the busiest airports, and a whole universe of new insights.
Table of Contents (23 chapters)
QlikView 11 for Developers
Credits
Foreword
About the Authors
Acknowledgements
About the Reviewers
www.PacktPub.com
Preface
Index

Ordering, peeking, and matching all at once


In the earlier sections, we have discussed three different functions commonly used in data transformation. We will now present a use case in which all three functions will complement each other to achieve a specific task.

The use case

We know that the IntervalMatch function makes use of closed intervals already defined in a table. What happens if all we have is a start date? To illustrate this scenario, look at the following screenshot:

As you can see, the End Date field has disappeared. However, there is a way for us to guess it and assign the corresponding value, based on the start date of the immediate following record. That is, if one record starts on 1-Feb-1998 and the immediate following starts on 1-Jan-2000, it means that the first interval ended on 31-Dec-1999, right?

In order for us to calculate the end date, we need to first sort the table values so that all corresponding records are contiguous, then "peek" at the start value from the next...