Automatic Historical Archive of Data for Comparison

[deltauser2006]

My database consists of information which is updated every quarter.
Forms will compare data from the present quarter to quarters past. I
need a way to make the database save a copy of itself every quarter and

then be able to have a form refer to that data through a comparison.
The historical data set would be created at the end of each quarter and

lock in all the values from that quarter. For example this quarter
(1st quarter 2006) I would need to refer to 1st quarter 2005 for a
comparison. Obviously a set of data for 1st quarter 2005 hasn't been
created yet so I would have to put data in manually but eventually once

the data was populated I would want it to do the comparison
automatically.

I realize this is an involved problem but if anyone could just give me
a general suggestion to get me moving in the right direction I would
really be grateful!!

 

[deltauser2006]

Here's the thing though, the data is constantly changing so basically
I'm looking for snapshots through time of the database. I'll explain
further. The data is for apartment rents and other information. So we
are constantly surveying and getting new rents (we do that every
quarter). Every quarter all the data has changed slightly. When we do
analysis we want to be able to look back at all the data from, lets say
a year ago. I would need to make a printout that had, for example:
Current Average Rent vs. Average Rent During This Quarter Last Year.
What I am trying to do is automate this process. I want the report to
recognize that it is currently the 1st quarter, that it should use the
data currently in the database for that number and that it should pull
last years comparison from the 1st quarter '05 data (Which obviously
would take 1 year of data being stored before it would function
seamlessly). Any tips on attacking that? I really appreciate any help
I can get. Thanks