Remember from the basic example that a dimension table contains a logical grouping of elements that describe the context of the facts and are typically joined directly to the fact table. In some cases it is appropriate to join a dimension table to another dimension table. This will create a "second layer" of dimension tables around the "first layer" that surround the fact table. The DIM_EXECUTIVE_INFORMATION table is an example of this. This is called an outrigger. Since only a few of the employees are executives, creating a new table to contain the data that is specific to the executives will keep the DIM_EMPLOYEE table from having to house this data with several blank rows.