When mapping in import you will be asked to define a key field, this is mandatory and you must define at least one:
With the key field you define which field from your import file is to be used for the assignment of the data records in seventhings.
Why is it so important for mapping?
When importing data, the key field is used to check whether this data record already exists in seventhings or the data record must be newly created.
Example:
If you select the scancode as a key field and have an object with e.g. the scancode 100001, then seventhings will check during the import whether this scancode already exists,
if yes, then during import all data will be updated or overwritten that belong to this scancode, e.g. the description, manufacturer or other data that you want to import for this scancode.
if no, i.e. seventhings doesn't know the scancode 100001, then this scancode will be newly created during the import together with all data that is attached to the scancode.
Also be aware that there are differences in room and object import!