It is not possible to insert a NULL value into a LOB column.
According to the ODBC Specification, there should be two ways to insert LOB NULL values when using DATA_AT_EXEC:
- The application calls SQLBindParameter with the data length set to SQL_NULL_DATA
- The application calls SQLPutData with the data length set to SQL_NULL_DATA
However, only the first of these alternatives is available due to a Teradata Database restriction.