Data Integrity
If you are updating data bought from a data supplier, why not protect the integrity of your data by using their unique account/contact numbering system. To ensure the suppliers numbering system is unique for you, ensure you prefix their number with a code for the supplier. For example a record bought from Dun and Brad with number 46879 becomes DB46879.
To handle this you need to create an Integration type custom field under Organisation or Person 1 (if you have a B2C type system). Access this from Configuration/Custom fields and select Organisation or Person 1 (if you have a B2C type system). Scroll to the bottom of the available fields and you’ll find a further 8 fields you can use to integrate your system. Create a field with the rule “Optional” and define as necessary. This field will now be available when you import data from your supplier.
Test this by uploading a sample import file and looking under the Create mode tab in the import function. You will see that your new field is offered as an optional way of identifying update and new records. This field will use the unique number to update existing data and create new records without duplication.

