"On Update" behaviour - default value on update

[Ste Hodges]

I've searched for an answer but can't find one relating to this.

I store data in a database that is to be accessed every hour from a third party app. This app looks for a value in an integer column (-1 if its a new record, 0 if its updated, 1 if the app has already seen it).

I want to be able to set the value of this column as and when updates are applied to rows.

I've set -1 as the default so any new rows get -1 (and the third party app therefore finds the record) but I want to set the column to 0 on every update (so the app knows its changed).

This is similar to "on update" but I think this can only be applied to a timestamp?

Is creating a trigger the only route? Can anyone help?

Thanks in advance.