You can select the appropriate unique identifier (UID) for your database. When your unique identifier is selected, it cannot be modified. Use the scenarios to guide you in choosing the correct unique identifier for your databases.
| Situation | Recommended option(s) |
|---|---|
| A database will only ever contain 1 contact record per email address. | Email as the unique identifier |
| A database or relational table will contain 1 or more contact record per recipient account but each row maintains a unique email address and web forms are used. | Email as the unique identifier |
| A database or relational table will contain 1 or more contact record(s) but each contact record maintains a unique email address and web forms cannot be used. | Email or custom defined unique identifier based on the account identifier and the email address |
| A database or relational table will contain 1 or more contact record(s) and email addresses may appear on multiple rows; web forms are not used. | Custom defined unique identifier to include the account identifier; may or may not include the email address. |
| A database will contain 1 or more contact record(s) and the same email addresses may appear on multiple more contact record(s); web forms are used or might be used in the future. | No unique identifier |
| A database is maintained by an external system and the uniqueness of the email address and identifiers is not known or is not assured. | No unique identifier |