Modelling the Relationship between Dimensions

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Modelling the Relationship between Dimensions

Post  monserob on Mon Mar 04, 2013 11:42 am

I work for an alarm installation company. In our transactional system we have two tables - site and system. The site table holds where the alarm system is installed and the system table relates to the alarm. A site can have more than one system and a system can as you'd expect only be installed in one site.

It makes sense for site and system to become dimension tables in a proposed data warehouse. If that assumption is correct then how would a BI user do an adhoq system count and also pull in one or more attributes from the site dimension e.g. a site type? Would we need to create a factless fact table to manage the relationship between these two dimensions?

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Re: Modelling the Relationship between Dimensions

Post  ngalemmo on Mon Mar 04, 2013 3:13 pm

You could do that, but would there not be a sale or installation event that provides that information as well?
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Re: Modelling the Relationship between Dimensions

Post  monserob on Tue Mar 05, 2013 6:30 am

The site and system records are created as part of an order release process, which we will be modelling; unfortunately information may not be available for systems that were installed prior to 2007. I guess we could create dummy order release fact records for those systems but I can't help thinking that this is a lot of work for something as simple as a system count grouped by site type. Am I missing something here?

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