KEY is also one of the allowed arguments following FORMAT in the DISPLAY command. Properties designated as keys are displayed in a separate section of the symbol.
Example
DEFINITION "Entity"
{
PROPERTY "Description"
{ EDIT COMPLETE LISTOF "Attribute" FROM "Data Element"
KEYED BY {Model, "Entity Name":"Name", "Name"} RELATE BY
DISPLAY { FORMAT NONKEY LEGEND "Non-Key Attributes" }...}
In the example above, the FORMAT KEY command places all attributes designated by the user as primary keys under the "Primary Key" legend on an entity symbol. The FORMAT NONKEY command places all non-primary-key attributes under the "Non-Key Attributes" legend on the entity symbol.