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Hello, I was recently tasked with preparing a presentation to our Data Warehouse team to cover some of the basics of Qlik Sense so that they understand the needs on the visualization end. One important topic I am trying to cover in this presentation is our data model and the features that Qlik Sense employs (e.g. associative data model, loading app into memory, etc.).
One of the things that I was going to talk about is how Qlik Sense internally indexes all unique values of a field to reduce duplication of memory. In my understanding, at the end of the data load every field has an internal index field created for unique values. For instance, say you have a table that contains demographic data for people:
Person | Ethnicity | Gender |
A | White | Male |
B | White | Female |
C | African American | Female |
D | Asian | Male |
E | White | Female |
At the end of the load script, an index table gets created for each field
Person:
Index | Value |
1 | A |
2 | B |
3 | C |
4 | D |
5 | E |
Ethnicity:
Index | Value |
1 | White |
2 | African American |
3 | Asian |
Gender:
Index | Value |
1 | Male |
2 | Female |
And then the original table just becomes
Person | Ethnicity | Gender |
1 | 1 | 1 |
2 | 1 | 2 |
3 | 2 | 2 |
4 | 3 | 1 |
5 | 1 | 2 |
But as I was preparing this, I realized that I don't remember how I came across this knowledge. I've tried searching for any documentation on this, but I can't find any and now I am uncertain if this is how Qlik Sense actually works.
Can anyone confirm this or point me towards some documentation on the subject?
This is the article I have been looking for my entire life! Lol, this is exactly what I needed. Thank you!
This is very interesting too:
https://community.qlik.com/t5/QlikView-Documents/Qlikview-Data-Storage/ta-p/1491335