You may need to add a new field to an existing entity database table to accommodate a new data.
A new field can be added to an existing table when a new UMF segment does not require an entirely new table.
Adding fields to an existing entity database table does not allow resolution on the new data, it is just a place to store data.
It is recommended that you should use a test database when verifying new configurations before applying those new configurations to your production environment.
It is recommended to use existing tables and fields to classify new data if at all possible.