Delete columns from a table when they’re no longer needed to store data. When a column is deleted from the table in the database diagram, it is also deleted from the database.
Caution This action cannot be undone once the database diagram or table is saved. The only way to restore a deleted column is to close the table or database diagram without saving changes.
To delete columns from a table
The column, any constraints attached to it, any relationships it participates in, as well as the data that’s stored in the column are removed from the database diagram. They are deleted from the database when you save the table or database diagram.