A database system includes a storage module containing a table having plural portions (e.g., rows). A lock manager places a table-level lock on the table for a first transaction, the first transaction updating a first row of the table. The lock manager converts the table-level lock to a lower level lock...http://www.google.es/patents/US6772155?utm_source=gb-gplus-sharePatente US6772155 - Looking data in a database system
