Databases Reference
In-Depth Information
At a general level, we can say that variables in QlikView are used in two
different ways:
• To store a value or string either static or based on a formula. This type of
variable can also be used to receive and interpret input from the user.
• To store an expression definition that can be used in charts. This is an
approach we explored in
Chapter 6
,
Building Dashboards
.
The main difference between the previously mentioned options is that one calculates
the output before sending it to the sheet object that makes use of the variable,
whereas the other stores only the definition of the expression and the object using it
is in charge of evaluating it and getting a result.
In this section, we will cover the use of variables up to an advanced level, but let's
first get the basics in order and move on from there.
Creating a variable
We've already worked through the process of creating a variable in a previous
chapter, and you've seen that it is fairly simple. However, let's make a quick
review of the steps involved in using our
Airline Operations
document. Open
the corresponding QVW file and create a new sheet so that we don't mess up the
objects already created. Name this new sheet
Variables
.
After practicing with some examples in a separate
sheet, we will apply the learned concepts by
extending our
Dashboard
and
Analysis
sheets.
Now, go to the
Variable Overview
window by using the keyboard shortcut
Ctrl
+
Alt
+
V
or by clicking on the
Settings
menu and selecting the
Variable Overview…
option, as shown in the following screenshot:
