On Great Deal Problems of Explanation on UPDATE Command of FoxBASE+FoxPro
Xu Guang · Journal of Heze Teachers College · 2004
The UPDATE command, notes that for each record in the current table/.DBF,can be multiple matching records in the update table/.DBF. If there are multiple matching records, the record in the current table/.DBF is updated by each of the matching records. If the current table/.DBF contains identical key field records, only the first of the matching records is updated.