In the all-in-one-deduplication, the postal address, telephone and fax number and the email address are deduped simultaneously. Opposed to the match functions, using every single one of the matching criteria, which is also available in the program, the all-in-one-deduplication offers relatively few configuration options. Only the degree of matching can be set for the deduplication using the postal address. Furthermore, using the field assignment, it can be indirectly determined whether the email address, the telephone number, and/or the fax number should be included in the comparison or not. These three criteria are only included in the comparison when a data field has been entered in the field assignment for this purpose. For duplicates recognised using the telephone number, fax number or email address, there is no designation in the “Degree of Matching” column in the manual post-editing.