I’m not sure if I do not understand the use of row in database properly or not, but my assumption is you are just wanting to save the values in the database. Since there would not be a known number of possible dates (because no known restrictions on start or end dates to know how many dates will be returned by any users interaction with the system), you’d likely want to store the values as a list of something. Optimally that list would be of date objects, so a data field of type date that is a list, needs to be in your database, on a data type that you need this information saved to.

I believe there is a free plugin called List of Dates that potentially can be used for this use case.

Start Date is the Start Date of the Range. Interval Type is Day. Interval is 1. The Number of dates is the dynamic expression of Range Start Date minus Range End Date formatted as days (you might need an additional operator like floor or ceiling to get it right).

Then save the the data field that is a list of dates, the value from the plugin element.