Implementing getLength()
Some databases require knowing at the beginning of the operation the total length of the data to be inserted into a row. Check the access module documentation for your database to determine whether this information is required. If so, you must implement the getLength() method:
size_t getLength(size_t rownum) const;
The rownum parameter has the same meaning as it has for onSend() above. This method is called just before the initial call to onSend() for each row to get the total length of the data being sent for the row.
Note that if the getLength() method is needed but not overridden from the base class, the inserting of data will fail.
