INDEXED_IO is a generic Compaq Ada package that provides input-
    output operations for access to and from indexed files.

    All of the file management input-output operations are also
    provided by this package (see HELP Ada Language_Topics File_
    Management).

    The package INDEXED_IO provides a generic READ_BY_KEY procedure,
    which defines input for the given element type. This procedure
    must be instantiated with an actual type parameter for the
    generic parameter KEY_TYPE; it may be instantiated with or
    without a value for the generic parameter DEFAULT_KEY_NUMBER.
    The range of values for DEFAULT_KEY_NUMBER is 0 to 254; a value
    of 0 (the default) designates the primary key.

    If the RELATION parameter to the READ_BY_KEY procedure is
    specified, it must have a value of EQUAL_NEXT, EQUAL, or NEXT
    (the default is EQUAL).

  Additional Information (explode) :

• READ
• WRITE
• UPDATE
• UNLOCK
• DELETE_ELEMENT
• END_OF_FILE