是的，您将能够更改12c中的表以启用时间有效性(请参见文档的ALTER TABLE部分:

Yes, you will be able to ALTER the table in 12c to enable Temporal Validity (see the ALTER TABLE section of the docs: http://docs.oracle.com/cd/E16655_01/server.121/e17209/statements_3001.htm#CJAEGCFI)

它通过将where子句转换为< =和">或为null"子句而起作用，因此，如果不需要，您无需更改固定日期.

It works by converting your where clause to a "<=" and "> or is null" clause, so you don't need to change the fixed dates if you don't want to.

汤姆·凯特(Tom Kyte)刚刚在他的博客上发布了有关此内容的文章，并列举了一些出色的例子: http://tkyte.blogspot.com /2013/07/12c-flashforward-flashback-or-see-it-as.html

Tom Kyte just posted on his blog about this today, with some execellent examples: http://tkyte.blogspot.com/2013/07/12c-flashforward-flashback-or-see-it-as.html