Alias PSN

If you need to send large objects to the database it might be convenient to send them in pieces. The chunkSize and chunkDelegate variables allow for this. If both are provided then the corresponding column will be populated by calling the delegate repeatedly. The source should fill the indicated slice with data and arrange for the delegate to return the length of the data supplied (in bytes). If that is less than the chunkSize then the chunk will be assumed to be the last one.