topic Re: Data Modelling in QlikView

Data Modelling

Tue, 24 Feb 2015 18:27:40 GMT

I have created a star schema data model by concaternating several tables.

The document reloads fine but when I check my Fact table in table view some of the data is missing but these fields contain data in the source table.

Please advise on how I can resolve this?

Re: Data Modelling

Tue, 24 Feb 2015 18:38:22 GMT

I think my attachment wasn't properly attached. Here it is

Re: Data Modelling

Tue, 24 Feb 2015 19:14:06 GMT

It's partially because you're using CONCATENATE I believe... if these tables have relationships you should be using JOINS so the tables match on fields they share. CONCATENATE simply mushes the tables together ignoring any matches. See here... Understanding Join, Keep and Concatenate For instance, you have a handful of tables that all have a field Customer which they would link on using a join.

Re: Data Modelling

Wed, 25 Feb 2015 00:09:45 GMT

Hi Tumelo,

You probably have done the correct thing by CONCATENATING all fact table.

It basically depends upon how do you want to analyze your data. In your current scenario if you write the expression like sum(NetSalesValue) and create a graph with some dimensions, you will get the correct results.

On the other hand if you join the tables which doesn't have the same granularity (no of dimensions) then your data may get duplicated and after aggregating you will get wrong results.

CONCATENATING fact tables which share at some common dimension is a suggested solution.

Hope this helps,

Anosh

Re: Data Modelling

Wed, 25 Feb 2015 09:23:25 GMT

Thanks Anosh!