1 best data before migrating to develop a program, similar to the point of downtime, how long downtime, application reinstated point in time.
2 (test data) is now a test environment to test it again, forming a program implementation, and then make a formal
3 time migration, pay attention to migrate part of the table space, parameter files, REDO file, TEMP table space, UNDO table space, SGA and PGA settings, backups, database character set and so on
Reproduced in: https: //my.oschina.net/u/204616/blog/545295