topic Re: schema for multiple facts in App Development

schema for multiple facts

ali_hijazi — Tue, 24 Aug 2021 10:21:09 GMT

Hello got multiple fact tables
I want to create a linktable / bridge table to link them together and thus create a schema
what are the rules in this case?
how do I choose the keys from each fact table and how to link them in the link table?
kindly advise

Re: schema for multiple facts

stevejoyce — Tue, 24 Aug 2021 10:52:05 GMT

Your link table has all common fields between your fact tables (example dimension foreign keys). Fact tables only contain the unique fields. The rest of your data model associates to the link table.

If your fact tables are similar in structure, you can choose to concatenate (union) fact tables instead of a link table.

Re: schema for multiple facts

ali_hijazi — Tue, 24 Aug 2021 11:11:27 GMT

So you mean fact tables link to the bridge table via the unique keys of each row or not necessarily?

Re: schema for multiple facts

stevejoyce — Tue, 24 Aug 2021 11:59:50 GMT

Yes. You'll need to add appropriate keys to the link table to associate to each fact, or create composite keys for each table with appropriate fields in qlik. It's essentially a synthetic table that qlik auto generates in this scenario.

Take a look at this post:

https://community.qlik.com/t5/Qlik-Design-Blog/Fact-Table-with-Mixed-Granularity/ba-p/1468238