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QlikView for Developers Cookbook

By : Stephen Redmond

4.4 (24)

QlikView for Developers Cookbook

4.4 (24)

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.

QlikView for Developers Cookbook

QlikView for Developers Cookbook

Credits

Credits

Foreword

Foreword

About the Author

About the Author

About the Reviewers

About the Reviewers

www.PacktPub.com

www.PacktPub.com

Preface

Preface

Free Chapter

Charts

Charts

Introduction

Creating custom pop-up labels on a bar chart

Creating a box plot chart for a simple data set

Using the wizard to create a box plot chart

Creating a "Stephen Few" bullet chart

Creating a modified bullet chart in a straight table

Creating a bar chart in a straight table

Creating a Redmond Aged Debt Profile chart

Creating a waterfall chart

Replacing the legend in a line chart with labels on each line

Creating a secondary dimension in a bar chart

Creating a line chart with variable width lines

Brushing parallel coordinates

Using redundant encoding with a scatter chart

Staggering labels in a pie chart

Creating dynamic ad hoc analysis in QlikView

Layout

Layout

Introduction

Changing the default object layout options

Changing the default selection color scheme

Modifying the green, white, and gray selection color schemes

Modifying the green, white, and gray selection color schemes in QlikView Server

Using containers as an alternative to multiboxes

Using the design menus to custom format a cell

Set Analysis

Set Analysis

Introduction

Using dollar expansion in Set Analysis to enable from-date and to-date selection

Using alternate states with Set Analysis

Using Set operators to exclude values from results

Using Set Analysis with a Date Island

Using Sets to avoid key tables

Advanced Aggregations

Advanced Aggregations

Introduction

Using TOTAL to calculate the percentage of total and subtotal

Using AGGR to calculate the percentage of the maximum value

Using AGGR to resolve a "Sum of Rows" issue

Creating a dynamic AGGR expression for a Group dimension using Dollar Expansion

Using RangeMax to return only positive numbers

Creating a dynamic Part-to-Whole pie chart

Creating a colored treemap using colormix

Using RangeSum to calculate a rolling total in a multidimension table

Showing only the top 3 values in a pivot table

Creating a Statistical Control Chart using Standard Deviation

Creating a Moving Range chart

Creating a control chart using Moving Range

Advanced Coding

Advanced Coding

Introduction

Extracting QlikView data to a Word report

Printing reports to PDF using PDFCreator

Creating a chart using a macro

Using VBS functions in charts

Data Modeling

Data Modeling

Introduction

Concatenation of fact tables to avoid loops and synthetic keys

Creating a Key/Link table in QlikView

Extensions

Extensions

Introduction

Creating a simple HTML extension

Creating a simple HTML table

Creating an interactive extension

Using external libraries with extensions

Useful Functions

Useful Functions

Introduction

Handling null in numeric fields or calculations

Using Dual to handle period name sorting

Parsing text to numbers and dates

Calculating Year To Date dynamically

Labeling a pie chart to replace the legend

Calculating the lowest or highest value in a range

Consolidating a date-time value into quarter hourly segments

Dynamically filtering by From/To dates

Script

Script

Introduction

Creating flags in the script

Replacing IsNull

Storing and dropping using a subroutine

Keeping a trace on things

Using the AND mode in listboxes

Using Exists and Keep to limit the data load

Setting the default display format

Setting the default sort order

Matching financial periods to dates

Handling partial reload in the script

Using Peek and Previous to calculate against loaded records

Creating a simple Gantt for a dashboard using Interval Match

Reading users from Active Directory

Getting a sub-URL using the Table wizard

Using parameters in Dollar Sign Expansion

Removing fields with a wildcard

Handling multiple subfolders in a script

Improving Performance

Improving Performance

Introduction

Reducing the number of distinct values

Creating counter fields to avoid Count Distinct

Creating flag fields to avoid Sum of If and other inefficient expressions

Denormalizing for performance

Security

Security

Introduction

Section Access gotchas

Blocking user access to a field using OMIT

Making all values available to Admins and Managers

Index

Index

Creating counter fields to avoid Count Distinct

Using a Count function is a very common use case in any type of reporting. However, it is also a very laborious calculation, requiring many more CPU cycles than, say, a Sum function. This is because a function like Sum is actually a very low-level function, operating almost at the CPU level, whereas a function like Count is more high-level, operating at the application code level. On a multi-threaded system (which means almost all systems nowadays), the Sum function will run across all cores whereas the Count function will only calculate on one thread.

If we can avoid Count functions, especially a Count function with a Distinct clause, then we will have a more efficient application.

Getting ready

Generate QVDs created in the Reducing the number of distinct values recipe.

How to do it…

These steps show you how to create counter fields to avoid Count Distinct:

Create a new QlikView file in the same folder as the QVDs. Load the following script:
```
LOAD...
```

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