On Sun, 15 May 2016 10:42:37 -0500 mikeegg1 <mikeegg1 at mac.com> wrote:
> I was once told of an idea (decades ago) of versioning data within a > table where one column has a real/float value that is the version > number. You can have a point-in-time database if: * each transaction has an id * DELETE is redefined not remove but simply to mark the row * UPDATE is redefined as DELETE + INSERT * every table includes both a transaction id and a deleted flag Every query would need "where transaction_id <= N and is_deleted = 'N'". There's your structure. Just a small matter of programming. ;-) --jkl
