1. A computer implemented method, comprising: receiving a plurality of source records from a plurality of data sources, each source record including a plurality of fields; determining that a match group of source records from different data sources relate to the same entity; automatically creating a single best new record for the match group based on field values from different source records in the match group, wherein said creating includes: assigning a first set of fields to a first survivorship group associated with a first survivorship rule, the first survivorship rule indicating that the first set of fields are trusted from a first source over a second source, assigning a second set of fields to a second survivorship group associated with a second survivorship rule, the second survivorship rule indicating that the second set of fields are trusted from the second source over the first source, and simultaneously ranking all source records in the match group in accordance with the first and second survivorship rules using a single query; calculating a single source record for each survivorship group based on a plurality of survivorship rule dimensions; identifying match groups that contain only a single source record, wherein said creating is not automatically performed for the identified match groups; and storing the single best new record.