Answer
When using the JOINITEM or RELATE operation, records in one theme are compared with records in another theme to find matching values to link the tables. There are two types of record relationships that can be used in ArcCAD:
One-to-one There is one record that directly corresponds to another (e.g., State Capitols to States).
Many-to-one You have many records that correspond to one other record (e.g., ZIP Codes to States).