Hi Darek,
this would be easy, if you could do this check with a "wizard" step. Then you could either use:
- Change item list values, to update all rows using a SQL query
- Use the for each operator introduced with BPS 2022. With this you can select the item list and use the 'change value of single field". In the action you can select a column from the item list and in the SQL query, you can reference the value of the field you are using to verify whether the row exists.
An alternative could be to use the "Form rule invoked after callback" in the configuration tab of item list. You could use the for each row to set a column to a value. The value will be returned by a prepared business rule, which has a parameter. This parameter will be set to the column value which you are using to check whether the row exists.
I haven't tested the callback approach but it could work.
Best regards,
Daniel