You can define a criterion (based on a column) as a key for each table that you add to an analysis realm. With the key, identical data is identified during data import and processed accordingly.
The values of the keys uniquely identify the rows of a table. During import, the key values of the preceding rows are compared to the key values of the rows to be imported. If the values match, the data is overwritten. Otherwise, the data is added to the existing table.