# Classification

## How to Activate the Value Check on Classes

| ### What to do:
| To work through this example, you must have completed the examples Fill the Attribute Pool, Assign Attribute Values to Attributes, Create a Class and Assign Attributes to a Class.
| Select Start > Classification > Classes. The Class mask is opened.
| Search for the class CLS-1100 wood screws.
| Select the Attributes tab. The attributes assigned to the class are shown.
| Select the attribute Length.
| Change to edit mode using .
| Change to the CHK field.
| From the selection list, select the value check that is to be used in this class: M: The field must contain a value from the attribute menu of the classification list, or has to be empty. If this is not the case, the data record cannot be saved. W: The field may contain a value that is not entered in the attribute menu of the classification list, or has to be empty. A warning is shown during storage. N: The field may contain a value that is not entered in the attribute menu of the classification list. No warning is shown during storage.
| To save the entry click .