Data Purging Strategy

[prem]

Dear List,

I need some inputs from you all regarding purging data from the database.

This is the requirement


We define a retention period for all the data in the system.
When the retention period is reached,  the data should be deleted, but then at a later time, some user might request for this purged data. So it must be possible to retrieve this data.

This is the strategy we have designed for this.

When the retention period is reached, move the data from the main database to an offline database. Then delete the data from the main database.

In the offline database, we cannot again keep it from long, so it has to moved to tapes. Now my question, how can we move this data to tapes and at the same time retrieve data from the tapes based on dates.
i.e, the user will ask for the data on a particular date, so it must be possible to retrieve data from the tapes based on a date and load it to the database tables.

Regards
Prem