Data consistency

The first set of best practices that we present on data modeling are those related to data consistency. This is one of the most important things we need to take care of when building QlikView documents. Let's look at some best practices that we can use to assure our data is concise and consistent.

Dealing with dimensions without facts

Sometimes, a dimension table can contain values that do not have any associated facts. To demonstrate this, let's take a second look at the data model we built in Chapter 4, Data Sources,and have been using ever sice:

1. Open the Airline Operations.qvw file.

2. Launch the Table Viewer by selecting File | Table Viewer or by pressing Ctrl + T.

3. Hover the mouse over the %Aircraft Type ID field in the Aircraft Types table, pay special attention to the Subset ratio value.

4. Next, hover the mouse over the %Aircraft Type ID field in the Main Data table, again paying special attention to the Subset ratio. What you will notice is that the Aircraft Types dimension...