Book Image

QlikView for Developers Cookbook

By : Stephen Redmond
Book Image

QlikView for Developers Cookbook

By: Stephen Redmond

Overview of this book

QlikView has been around since 1993, but has only really taken off in recent years as a leader in the in-memory BI space and, more recently, in the data discovery area. QlikView features the ability to consolidate relevant data from multiple sources into a single application, as well as an associative data model to allow you to explore the data to a way your brain works, state-of-the-art visualizations, dashboard, analysis and reports, and mobile data access. QlikView for Developers Cookbook builds on your initial training and experiences with QlikView to help you become a better developer. This book features plenty of hands-on examples of many challenging functions. Assuming a basic understanding of QlikView development, this book provides a range of step-by-step exercises to teach you different subjects to help build your QlikView developer expertise. From advanced charting and layout to set analysis; from advanced aggregations through to scripting, performance, and security, this book will cover all the areas that you need to know about. The recipes in this book will give you a lot of the information that you need to become an excellent QlikView developer.
Table of Contents (19 chapters)
QlikView for Developers Cookbook
Credits
Foreword
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Removing fields with a wildcard


This particular recipe was inspired by a client of mine who was loading data from a shared set of QVDs. There were a lot of fields in the QVDs that he didn't need and he was wondering if he could; rather than manually pruning the load statement, automatically remove fields based on a wild card (all the fields that he wanted removed had the word CUSTOM_ at the beginning).

Unfortunately, we cannot use wildcards in the Drop Fields statement. There are a couple of useful functions that we can use to achieve this.

Getting ready

Load the following script:

MyTable:
LOAD * INLINE [
F1, F2, F3, F4
1, 2, 3, 4
];

Rename Field F1 to NewField;
Rename Field F3 to NewField2;

How to do it...

Use these steps to see how to remove fields with a wildcard:

  1. Add the following script:

    Let i = 1;
    
    Do While i <= NoOfFields('MyTable')
    
      Trace Getting Field $(i) From MyTable;
      
      Let FieldName = FieldName($(i), 'MyTable');
      
      Trace FieldName = $(FieldName);
      
      If '$(FieldName)' Like...