Link the ID or link the dates?

[Applicable88]

Hi!

I just happened to find an old interesting blog from HIC:

I think he made a very good point. I have the same issue , where I dont't know if I should connect the dates of a Shelf ID with their Materials and Location  to a error report (where reports are made if a electric shelf made trouble. buth there are also many other errors recorded totally unrelated to the shelf system, since its showing ALL error reports within the company) . The other problem is that the Shelf ID contain to date columns "valid start", and "valid until." A so called "slowly changing dimension". I heard its solved with loading it as intervalmatch, but I have a conflict here since there are also other tables involved.

1. Question: Whats best solution in my case? Connect which keys together?

2. Question: Other than that, if I understand it right HIC  said he put ONE Date Table and connect  it to both of the mentioned table? And then a additional Master Calendar? Why he didn't he link the two tables own Date keys DIRECTLY and and why use a  unconnected Master Calendar. I don't understand that purpose. 

Maybe @hic personally can add some information....

Thanks in advance. 

Best.

[hic]

That post is from 2012.

I and some other people thought a lot about this problem at the time. We found a good solution, and some time later I wrote a blog post about it: https://community.qlik.com/t5/Qlik-Design-Blog/Canonical-Date/ba-p/1463578

The idea is to link the data using the proper key - not the date - but make a data model so that you have an additional date field that is relevant for both original dates.