Next, let's build some dimensions. As this is one of the more complicated steps in the cube design process, it's a topic we'll return to again in the future chapters when we need to deal with more advanced modeling scenarios. Right now, we'll concentrate on the fundamentals of dimension design.
Running the New Dimension wizard will give you the first draft of your dimension, something you'll then be able to tweak and tidy up in the Dimension Editor afterwards. The first question you'll be asked, in the Select Creation Method step is how you want to create the new dimension and there are effectively the following two choices:
Create the dimension from an existing table or view in your data source (the Use an existing table option)
Have SSDT create a dimension automatically for you and optionally fill it with data (the other three options)
The Select Creation Method step of the New Dimension wizard is shown in the following screenshot: