A relationship is a connection between two or more contacts. For example, some contacts may be children of other contacts, who are the parents. Some contacts will be employers of other contacts—employees.
This recipe will show you how to import relationships properly. We will use the built-in employer-employee relationship.
Navigate to Administer | Customize Data and Screens | Relationship Types and check that the employer relationship exists and is enabled.
Import all the contacts that will be employers. These will generally be organization contacts.
Now import all the contacts that will be employees. Make sure you have a unique identifier for each contact.
In the preceding data, the Key column contains a unique identifier. The Organization column contains the name of the employer.
Now import the individual contact data again, but this time we will import the relationship.
Navigate to Contacts | Import contacts and set your import.