In the transformation options, a type of data transfer can be defined. With the transfer option to
Replace existing data, all data in the target data group will be replaced. The option to
Attach all data will allow you to keep existing data in the target data group. The transferred
data will be added to the file.
Selecting the option to Attach new data will show all fields of the target data group in the
right-hand area of the window. Select the field here whose value can be used to identify a data
record as new. This field must be connected with a corresponding field of the target data group in
the field assignment in order for the value to be transferred from the source data upon each
import.
The option to Refresh existing data, attach new data corresponds to the Attach new
data option, with the difference being that existing records in the target data group will be
updated, i.e. refreshed, if changes were made to the source data group since the last update.