topic Data model in QlikView

Data model

vvvvvvizard — Thu, 02 Nov 2017 10:43:40 GMT

Good day

Attached is a pic of the data model

The model is accurate

Its not too slow , a little , no one is complaining yet

its 14GB in size

One fact table and the rest are dimension tables

I want to follow data modelling best practices , should i combine the dimension tables together

Getting to the star schema from here is easier said than done , any tips ?

Re: Data model

micheledenardi — Thu, 02 Nov 2017 10:59:16 GMT

I think you can use Document Analyzer V3.0 Update Available to check if all the dimensions are used at layout level and drop the unused fields.

After that you have to join() and applymap() your tables (where possible).

Yes, easier said than done.

Check also this link and the attached files.

https://www.quickintelligence.co.uk/perfect-your-qlikview-data-model/

Re: Data model

Sergey_Shuklin — Thu, 02 Nov 2017 11:50:50 GMT

Hello!

If you want to make some cleanings so for the start it can be:

1. Order this chaos! Sort tables by meanings and theme, by links and key fields;

2. Join all that can be joined without changing on cheksum;

3. There can be some trash tables without any help in front-end (and they can be dropped in the script).

As the finish model it should be a fact table with multiple dictionaries.

Re: Data model

vvvvvvizard — Thu, 02 Nov 2017 12:18:12 GMT

last question , when can two tables not be joined . Some tables i joined i got incorrect results in front end , so i tried different combinations left , outer , inner , concateneate which is making me think some tables just cant be joined , is this true ?or can all tables be joined in some way

Re: Data model

Sergey_Shuklin — Thu, 02 Nov 2017 12:27:31 GMT

You should be careful with joining and not all tables can be joined without data corruption.

If it happens, so may be there is a way to transform, separate or combine this table somehow.

This is individual for every model.

Try to make it step by step.