Restrictions on NonUnique Keys

The following restrictions apply to the use of a non‑unique key:

TRANSMIT statements and debugger breakpoints result in CICS syncpoints. They are not restricted in any way if the access key is unique. For a non‑unique key, the TRANSMIT or breakpoint occurs, but the execution of a FOR EACH/FIRST statement cannot resume thereafter. Any attempt to resume execution under such conditions terminates the run with an error message.
Use of the CHECKPOINT and BACKOUT statements is subject to the same restrictions on the resumption of a FOR EACH/FIRST statement using a non‑unique key.
The execution of a FOR EACH statement based on a non‑unique key for a data set that was updated cannot resume following the update or deletion. This restriction affects all nested dataviews on the same data set. If an attempt is made to resume execution under such conditions, an error message is issued, and the run terminates.