A system and method for reading a data record from an input file only once, processing that data record according to one or more reference files, and then writing out the cleansed and updated data record to a target file such that the data record is read and written to remote storage only once, thereby making a single pass through a given database of data records. Each data record (comprising of multiple data elements) of the input file is reviewed, verified, and corrected against one or more reference databases containing similar information, assigned a unique identifying key, and, optionally, appended with new additional data elements of a matching data record from a new-data database.