How does K4 work?
The data is then read back on-the-fly from the SQL database when the object is refreshed.
K4 uses its web service for write-back. The web service receives from the K4 object the new/changed data together with the Qlik® / Tableau® document current filters and the user id: it compares these data with the structure of the SQL table to check that it has all the information (e.g. primary keys) it needs to create/update records in the table.