Analysis Services
Select the Key Column (Mining Model Wizard)
In this step of the wizard, you select the column containing the case key, which is the column in the dimension table that uniquely identifies the case you want to analyze in the mining model.
Options
Case key table
Select the dimension table that contains the case key column. This option is available only if you specified Multiple tables contain the data in the Select case tables step.
Case key column
Select the column from the dimension table that contains the case key.