Dimension/measure group relationships

So far we've seen dimensions either having no relationship with a measure group or having a regular relationship, but that's not the whole story: there are many different types of relationships that a dimension can have with a measure group. Here's the complete list:

• No relationship

• Regular

• Fact

• Referenced

• Many-to-Many

• Data Mining

We'll discuss many-to-many relationships in the next chapter because they are an important topic on their own, but before that let's talk briefly about the relationship types we've not seen so far.

Fact relationships

Fact or degenerate dimensions are, as we saw in Chapter 1, dimensions that are built directly from columns in a fact table, not from a separate dimension table. From an Analysis Services dimension point of view, they are no different from any other kind of dimension, except that there is a special fact relationship type that a dimension can have with a measure group. There are in fact very few differences between a fact...