host-variable          A valid host language variable.

    db-handle              Database handle. A host variable used
                           to refer to a specific database you have
                           invoked. For more information see the
                           entry on the Database Handle clause.

    relation-name          The name of a relation in the database.

    field-name             The name of a field in a relation. For
                           example, once you have defined E as
                           the context variable for the EMPLOYEES
                           relation, E.LAST_NAME is a value
                           expression that refers to a value from
                           the LAST_NAME field of EMPLOYEES.