Coding INVALID KEY phrases
You can include an INVALID KEY phrase
in READ, START, WRITE, REWRITE,
and DELETE statements for VSAM indexed
and relative files. The INVALID KEY phrase is given
control if an input or output error occurs due to a faulty index key.
About this task
You can also include the INVALID KEY phrase
in WRITE requests for QSAM files, but the phrase
has limited meaning for QSAM files. It is used only if you try to
write to a disk that is full.
Use the FILE STATUS clause
with the INVALID KEY phrase to evaluate the status
key and determine the specific INVALID KEY condition.
INVALID KEY phrases differ from ERROR declaratives
in several ways. INVALID KEY phrases:
- Operate for only limited types of errors.
ERRORdeclaratives encompass all forms. - Are coded directly with the input or output statement.
ERRORdeclaratives are coded separately. - Are specific for a single input or output operation.
ERRORdeclaratives are more general.
If you code INVALID KEY in a statement
that causes an INVALID KEY condition, control is
transferred to the INVALID KEY imperative statement.
Any ERROR declaratives that you coded are not performed.
If you code a NOT INVALID KEY phrase, it is performed
only if the statement completes successfully. If the operation fails
because of a condition other than INVALID KEY, neither
the INVALID KEY nor the NOT INVALID KEY phrase
is performed. Instead, after the program performs any associated ERROR declaratives,
control passes to the end of the statement.