The default isolation level for Oracle is read committed. This degree of isolation is
appropriate for environments where few transactions are likely to conflict. Oracle
causes each query to run with respect to its own materialized view time, thereby
permitting nonrepeatable reads and phantoms for multiple executions of a query, but
providing higher potential throughput. Read committed isolation is the appropriate
level of isolation for environments where few transactions are likely to conflict.
来自 “ ITPUB博客 ” ，链接：http://blog.itpub.net/10599713/viewspace-988999/，如需转载，请注明出处，否则将追究法律责任。