The key-of-reference specifier can optionally accompany the key- field-value specifier; it designates the key-field index that is searched to find the specified key-field value. A key-of-reference specifier takes the following form:

KEYID = kn

kn

Is an integer expression, called the key-of-reference number, that designates the key-field index to be searched.

The key-of-reference number is an integer value in the range 0 to 254. A value of zero specifies the primary key, a value of one specifies the first alternate key, and so forth.