问题
Tom Kyte describes temporal tables here:
temporal tables are tables that can return the answer that existed at a point in time -- you can ask the table to return the answer that existed at midnight last night, instead of the answer that exists right now
Do such tables exist in Oracle? I can't find documentation of them. How can I create one and use it? He says they exist in databases, although he doesn't say that they do in Oracle nor any other product. Is this a conceptual thing not implemented?
回答1:
Well, I believe you mean to get the data state as it was some time earlier than now. In this case Oracle suggests FLASHBACK QUERIES:
SQL> select * from t where x in (1,2,3);
X Y
---------- ----------
1 1
2 2
3 3
SQL> delete from t where x in (1,2,3);
SQL> commit;
SQL> select * from t where x in (1,2,3);
No rows selected
SQL> select * from t as of timestamp(systimestamp - interval '2' minute) where x in (1,2,3)
2 /
X Y
---------- ----------
1 1
2 2
3 3
Oracle describes this option there
http://docs.oracle.com/cd/B12037_01/appdev.101/b10795/adfns_fl.htm#1008580
As of temporary tables - plese see this reference:
http://docs.oracle.com/cd/B28359_01/server.111/b28310/tables003.htm#ADMIN01503
来源：https://stackoverflow.com/questions/21139448/temporal-tables-in-oracle