1 The complete file declaration would include the
attributes FILE, RECORD, and ENVIRONMENT; if you use either of the options
KEY or KEYTO, it must also include the attribute KEYED.
2 The statement "READ FILE(file-reference);" is equivalent to the
statement "READ FILE(file-reference) IGNORE (1);"
3 The expression used in the KEY option must be a sequential record value, previously obtained
by means of the KEYTO option.