On Wednesday 13 February 2008 22:06:54 Don Dwiggins wrote: > [EMAIL PROTECTED] wrote: > > we've put such a notion in our db, so the db knows what > > model-version it matches. Then, at start, depending on the > > versions one can decide which migration script to execute (if the > > db should be made to match the py-model), or which feautures to > > drop (if py-model should follow the db). btw there should be some > > tricky strategy as of what to call "db-model-version" and when > > that "version" really changes. > > This is getting into a big area: the problem of version > control/configuration management for databases its not any bigger than any other configuration management of something structured that is deployed in the field... as long it consists of pieces and these pieces can go/combine wrong... > ...... > (Just having a realized > "object-level schema" should be a big step forward.) mmm this is going slightly offtopic, but there might be many levels of modelling (db-model - mapping - obj-model - concept-model - behavioural-model - ... - philosophy-model if-u-want). The more the merrier ;-) i.e. the easier to change something without affecting something else on a far-away-level -- but is harder to grasp, takes longer to develop, and needs more initial investment. But on a long run pays off very well - of course IF there is no long run, no point doing it. e.g. Right now i have a bitemporal machine applied even over some part of the code of the system, organised as sort of read-only db/repository of replaceable pieces of code. And changes of piece in this "repository" are treated same as changes in the salary of someone - maybe less dynamic but still changes...
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