· By HeyData team
Henric Cronström’s Technical Briefs, revisited for Qlik Sense
Some technical papers age well. The Technical Briefs Henric Cronström published at Qlik in 2012 and 2013 are among them: with worked examples, they explain how the associative engine handles joins, missing values, intervals and hierarchies. More than ten years on, they remain references for anyone building with Qlik.
These papers were written for QlikView. The engine’s logic has not changed: what held true in a QlikView script still holds in the Qlik Sense data load editor. So we revisited each of them to produce a short summary, adapted to Qlik Sense, with redrawn diagrams.
Who is Henric Cronström?
Henric Cronström worked at Qlik. Under the handle “hic”, he published on Qlik Community a series of Technical Briefs and blog posts on data modelling and on how the engine works. Their quality lies in their method: start from a concrete problem, show the data, then explain why the solution works.
The series
Each article takes one paper, summarises its key ideas and adapts them to Qlik Sense (SaaS and Client-Managed). Attribution appears at the top and at the end of every article.
- Joins and lookups in Qlik Sense: when to join, when to use
ApplyMap, and how to avoid duplicated rows. - NULL and missing values: what Qlik treats as missing, and what that changes in calculations and selections.
- Generic keys: linking data at different granularities, such as budget and sales.
- Generating missing data: filling in missing dates, balances and combinations in the script.
- IntervalMatch and slowly changing dimensions: linking an event to the right period or the right version of a dimension.
- Hierarchies: turning a parent-child table into usable levels, then into aggregations and access rights.
- Incremental load with QVD files: reloading only what has changed, depending on whether the source appends, updates or deletes rows.
These articles draw on papers published by Qlik: six Technical Briefs by Henric Cronström and a presentation on incremental load whose author is not credited. All credit for the original content goes to its authors; the Qlik Sense adaptation, and any errors in it, are HeyData’s.
These topics are at the heart of our Qlik Sense Developer course and of our consulting work.