Sets the name of the file where blobs are going to be read from or written into. Without calling this function, px_get_record() or px_retrieve_record() will only return data in blob fields if the data is part of the record and not stored in the blob file. Blob data is stored in the record if it is small enough to fit in the size of the blob field.
Calling this function twice will close the first blob file and open the new one.
Resource identifier of the paradox database as returned by px_new().
The name of the file. Its extension should be .MB.