Recover deleted oracle flashback point

It sounds like Oracle Total Recall may fit your needs:

Regulatory oversight such as Sarbanes-Oxley, HIPAA, and Basel-II, as well as internal audits, require companies to keep historical data available for long periods of time. Oracle Total Recall, part of Oracle's comprehensive portfolio of database security solutions, works with Oracle Database 11g, Enterprise Edition to help companies store their data in secure, tamper-proof databases while keeping it accessible to existing applications

The documentation states that it can support refactoring:

In Oracle Database 11g Release 1, the Add Column DDL operation is supported with Flashback Data Archive. With Oracle Database 11g Release 2, the following DDL operations are supported, with full support for Flashback queries across all associated changes:

• Add, Drop, Rename, Modify Column

• Drop, Truncate Partition

• Rename, Truncate, Drop Table

For more complex DDL – upgrades, split table, etc. – the Disassociate and Associate PL/SQL procedures can be used to temporarily disable Flashback Data Archive on specified tables.

Firstly, you must enable flashback. In SQL*Plus as SYSDBA:

shutdown immediate;
startup mount;
alter database flashback on;
shutdown immediate;
startup;

Next before your load operation, create a restore point:

create restore point before_load;

Now do you work, and when you're done:

shutdown immediate;
startup mount;
flashback database to restore point before_load;
shutdown immediate;
startup;

And your data is back as it was. You can repeat this as many times as you like, and when you are done, drop the restore point. HOWEVER the commenters are correct; you should leave the constraints enabled and just defer them.