Reducing the number of distinct values

QlikView's columnar data storage method is extremely efficient at storing data because it does not store repeating values. Each unique value is only stored once. This means that, in general, a QlikView in-memory data set will always be much smaller than the original data source.

This efficiency is lost, however, when the data is highly distinct. The more distinct the values that exist within the data, the more space that QlikView will need to store it in memory. The worst offenders for this are often ID fields and time stamps, and if we can remove these, then we will make our document more efficient.

Getting ready

Load the following script:

// Build a list of city/countries
City_Country:
Load * Inline [
  CityID, City, Country
  1, Boston, USA
  2, New York, USA
  3, Los Angeles, USA
  4, Mexico City, Mexico
  5, Vancouver, Canada
  6, Montreal, Canada
  7, London, UK
  8, Manchester, UK
  9, Berlin, Germany
  10, Paris, France
];

Store City_Country into...