A standing instruction for the node to run one action of one accepted script, with fixed args, on a cron expression in the node time zone, until its lifetime ends — or a watch, a reference's own schedule, which names no script and no action because each firing derives the reference's recipe afresh (YmerNode.Schedules § Watches).

A row in the node database, addressed by a name whoever added it chose — morning-report — which is unique on the node and fixed: renaming is removing and adding again. A name takes lowercase letters, digits, - and _, starting with a letter or digit: the throttle's rule, YmerNode.Script.throttle/0, so the names people type, hyphens and all, need no quoting at a shell.

The script is held by its row, and the row's delete takes the schedule with it: the foreign key cascades, so removing a script can never leave a schedule pointing at nothing. A script's code replaced keeps its row, so a schedule follows the name to whatever is accepted under it at each firing. The script and the action are fixed at add; the cron expression, the args and the end are what update changes. A watch is held by its reference the same way, and a database CHECK keeps every row naming a script and its action or a reference, never both; one reference holds at most one watch.

ends_at is where the lifetime ends; at or past it the schedule is expired and fires no more. The last_* fields are the last run, and nothing before it (YmerNode.Schedules.LastRun).