Is a Fact table needed in the Presentation layer?

Jerry S.

I was looking at an RPD recently that someone else developed. Although they have

a Fact dimension in the business layer, they do not have one in the Presentation layer.

Instead, they incorporated the facts into other dimensions in the Presentation layer.

For example, a fact might be student count, so instead of having a Fact Dimension

in the Presentation layer with Student Count in it, they included Student Count in the

Student dimension of the Presentation layer.

The developer told me that as long as the Fact table is in the

BMM, there is no need to include it in the Presentation layer.

Is this ok, or could it potentially cause problems?

Gianni Ceresa

Hi,

First better to call it Fact or Fact table but not Fact dimension as these are the 2 things you have in a BMM: facts and dimensions (so it can't be both in the same time).

In the BMM a fact logical table is mandatory, but the presentation layer is just about presentation.

So there is nothing mandatory, you can also put all the logical columns of all your logical table of a BMM into the same presentation table.

So it will not cause problems, you will just spend 5 seconds more when looking if all the columns of your BMM are exposed in the presentation layer (but not mandatory at all) as they don't follow the same organisation.

But not a problem at all.

The presentation layer doesn't follow any fixed structure, it must really be designed to best match your users and make their life easier allowing them to find all the objects easily. Maybe logic for them, not really for you ... But not a problem