Check this post. Load screen not showing - #5 by ImranTariq
I made this to import a csv file into the database in the app.
bottom left: csv_import_connection: the path to the file online
call.csv_import_connection is the call to the block on the right.
The csv file consist of multiple items per line. What happens is:
Empty the database
loop through the csv file and put every row(line in the csv file) in the apps database. The first element of each line is the unique identifier for the row.