Using table auditing in order to have "snapshots" of table

Question

I need a solution for the following problem:

I will have a table in SQL server 2008 that will be changing daily. It's a small table with maybe 5000 rows at most and around 5 fields.

The client will need the ability to view all the data in the table the way it was at a given point in time. For example "show me what all the data looked like in the table 2 weeks ago".

Someone had mentioned that auditing the table with http://autoaudit.codeplex.com/ would solve this problem.

My questions:

1. Is there a solution to this problem that would involve simple auditing?
2. If so, then how would i use auditing to solve this problem?
3. Is there a different solution already in existence for this sort of challenge so that I do not have to reinvent the wheel?

Answer 1

Have an auditing table that get's manipulated by triggers. Something like:

create table YourAuditTable
(
    -- all of your source table's columns
    CreateDate datetime not null,
    DeleteDate datetime null
)
go

And your trigger would look like this:

create trigger AuditYourTable
on dbo.YourTable
after insert, update, delete
as

    if exists(select * from inserted)
    begin
        if exists(select * from deleted)
        begin
            -- this is for an update
            update YourAuditTable
            set DeleteDate = getdate()
            where YourIDCol in (select YourIDCol from deleted)
        end 

        -- this is just for an insert
        insert into YourAuditTable
        select *, getdate() as CreateDate
        from inserted
    end
    else
    begin
        -- this is just for a delete
        update YourAuditTable
        set DeleteDate = getdate()
        where YourIDCol in (select YourIDCol from deleted)
    end

go

What this will allow you to do is query your audit table for a point in time. In other words, just use DATEDIFF to determine if a row was created prior to that given point in time, and deleted after it (or not deleted at all).

EDIT

To query your audit table for point in time data:

select *
from YourAuditTable
where CreateDate <= @PointInTimeDateTime
and
(
    DeleteDate is null or
    DeleteDate > @PointInTimeDateTime
)