Any thoughts about this?....

Thanks!

Jonathan Neve.

Jonathan Neve wrote:

>Jim Starkey wrote:
>
>
>
>>Jonathan Neve wrote:
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>>
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>>
>>>Any ideas about this?
>>>
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>>>
>>>>So here it is. Why not create a sort of "undo-after-commit" feature,
>>>>whereby old versions of a record could be kept indefinitely, and if
>>>>necessary, restored of viewed?
>>>>
>>>>What might be good would be some sort of trace file, in
>>>>which, all obselete record versions are dumped, as and when they become
>>>>obselete. Then, there could be a simple API (or perhaps an SQL
>>>>extention) that could be used for loading old record versions back into
>>>>the DB, and also for purging out old versions periodically...
>>>>
>>>>
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>>>>
>>This has come up about a dozen times over the years, often in the
>>context of rolling back to an earlier revision of a CAD project.
>>
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>Hmm. Doesn't sound too promising... :-)
>
>
>
>>Everytime we've look at it in depth, we've come to the same conclusion,
>>which is that the application semantics need to be a great deal richer
>>than can be provided by a low level hack and vary signficantly from
>>application to application.
>>
>>
>>
>>
>Well, yes, I can understand this. I understand that something like
>rolling back to a previous version of the database, in one smooth, neat
>operation would be impossible to do at a low level, since the database
>structure isn't known at that level.
>
>However, wouldn't it be possible to simply keep the old record versions,
>and _make them accessible_, through a simple syntax? I don't mean that
>the database should automatically be able to do any kind of restoration,
>but simply that it could be made accessible, exactly as though (from the
>end-user perspective), it were simply another table, against which a
>subset of the standard SQL statements could be executed.
>
>Perhaps this is a simplistic approach, I'm no expert at this; but if
>so... in what way?
>
>Why wouldn't the syntax I proposed in my post (or something of that
>sort) be usable? It seems to me that it would be in effect, just as
>though we were accessing an external database (which feature, if I
>understand correctly, is being planned on).
>
>Why wouldn't this work?
>
>Thanks!
>
>Jonathan Neve.
>

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