When assigning a domain to a field in an attribute table, the following error is returned:
Error: The length of the value exceeds that of the field. [<field name>]
This error is also returned when running the Assign Domain To Field tool.
The domain name has exceeded the field length. The field length can be viewed from the Field Properties in the attribute table.
Note: To access the Field Properties, right-click the field in the attribute table and click Properties.
Reduce the domain name to be below the value of the field length or increase the field length to accommodate the domain name. For more information on modifying the length of a domain name, refer to ArcMap: Modifying and deleting attribute domains. For more information on increasing the field length, refer to ArcMap: Modifying field properties.
Note: When modifying the field properties, the Length value can be increased or decreased if the table or feature class does not contain data. If the table or feature class contains data, the field length can only be increased. Alternatively, users can create a new field with a maximum length of 255 characters, and set the new field to mirror the data of the original field before assigning a domain to the field. For more information, refer to How To: Increase the character length for a text field in ArcMap.