Functional differences in datatype conversion and error handling between bulk copy and express transfer are:
Datatype conversion
In bulk copy transfer, data being transferred is converted into intermediate Open Server datatypes.
In express transfer, the ODBC driver converts the datatypes automatically, and no conversion takes place in ECDA Option for ODBC.
Error handling
If a datatype conversion error occurs, bulk copy transfer supports error handling as defined in “Bulk copy and express transfer errors”.
Express transfer has only simple error handling: If an error occurs, it aborts the entire batch of rows if BulkCommitCount is greater than 1.