Add and Update existing table data with data from a form

I have a general problem that I am trying to solve in coda. I have a coda form that stores the responses in a table. I want to use that coda form table data to update another existing table. The coda form table data may represent new data in the existing table or it may already exist in the existing table. I need to match a “key” in the form data to the same value in a row in the existing table then update the column data for that row. I don’t see a way to check the existing table to match on a row before updating the columns in the row.

For example:
The existing table with rows represent buildings. Each row has a building ID column along with additional columns representing attributes of that building (address, number of stories, etc.). My form is used to update the attributes of the building specified on the form. So, I need to use the building ID specified on the form to find the row in the building table for the specific building then update the attributes of the building from the fields on the form.

From what you’ve posted it sounds like you need the AddOrModify action!

Heres some documentation on how to use that formula along with examples, and activities