The primarykey property, @openapi.openedge.entity.primarykey, is added at the entity level in the schema to specify the primary key of an entity.

Progress Developer Studio for OpenEdge generates an annotation for the primary key if the primary index is unique.

When you generate a Business Entity class file from an express Data Object project or from a database table in the New Business Entity wizard, Progress Developer Studio for OpenEdge reads the database for information about the primary keys defined on the table and accordingly adds the primarykey annotation above the temp-table definition.

Sample primarykey annotation: 

@openapi.openedge.entity.primarykey (fields="EmpNum"). 
DEFINE TEMP-TABLE ttBenefits BEFORE-TABLE bttBenefits 
FIELD EmpNum AS INTEGER INITIAL "0" LABEL "Emp No" 
INDEX EmpNo IS PRIMARY UNIQUE EmpNum DESCENDING.

You can manually change the value of the primarykey annotation in the Business Entity class file.