Delete a Table (SSAS Tabular)
In the model designer, you can delete tables in your model workspace database that you no longer need. Deleting a table does not affect the original source data, only the data that you imported and were working with. You cannot undo the deletion of a table.
To delete a table
Right-click the tab at the bottom of the model designer for the table that you want to delete, and then click Delete.
When you delete a table, the entire tab that the table was on is deleted.
If any measures were associated with that table, the definition of the measure will also be deleted.
If you created any calculated columns using that table, columns in that table are also deleted; any calculated columns in other tables that use columns from the deleted table will display an error.