I'm creating a Custom Business Object which I intend to act as a database for customers that have attended paid for training and seminars. The database is simply to log the name, data and some other basic information regarding the training course/seminar. What I'm uncertain of, however, is how to associate an entry with an existing contact. For example, if an existing contact attended a seminar then ideally one of the columns would allow users to insert the contacts Marketing Cloud ID thus connecting the relationship. This could then be used to segment contacts who attended historical courses/seminars which have been maintained in the database.
Thank you in advance