KeyOnly

The READ statement's KEYONLY parameter allows you to read both the key and the record number in a keyed file without reading the corresponding record in the master file. This feature was implemented to return the key if the master file record is locked and is being read by key. It can also be used to obtain keys sequentially, without the overhead of reading the master file.

The KEYONLY parameter is valid only for files opened INPUT KEYED or OUTIN KEYED. It may be used with positional parameters to specify the key that is to be read. If no positional parameter is specified, the next key will be read. FORM statements corresponding to the key length and B 4 for the record number should be used. If the record length of the master file is not at least four bytes more than the key length, the record number is not returned.

Read file KEYONLY without having read a master record to allocate a buffer caused the task to hang. BR has always required a master record to be read before accessing a file KEYONLY. Now this error condition produces BR error 0718.

While Business Rules! reads only the key file when the KEYONLY parameter is used, it does move the file pointer in the master file to the position of the record just read.

Note that it is very important to keep the key file updated if this feature is to be used. Otherwise, READ with the KEYONLY parameter could return an incorrect record in a situation where a master file record is deleted or rewritten after a READ with a REC= parameter.

A REREAD, DELETE, or REWRITE following a READ with the KEYONLY parameter will return an error.