Any non-null value can be typed as String. A String can be anything.
NOTE: If a column of values fails to match another data type, the column is typed as String data.
The length of an individual string value is limited only by the limit applied to an entire row of data, which is approximately 1 MB of characters.
NOTE: On export to relational systems, string lengths are limited to 256 for performance reasons.As needed, this limit can be raised for all applicable relational systems. For more information, see Configure Data Service.