Stuart McCulloch wrote: > interesting, sounds very similar to a distributed SCM like git, > especially wrt. managing changesets and using SHA hashes > > can there ever be a generic migration service - one that does > the safest possible population, but would leave bits unfilled? > or should every schema change also provide an associated > migration snippet (or mapping) that can handle that change?
There's tons of opportunity for innovation here, but my intuitive guess is that there will be a base migrator that uses guessing to do it. For example, property with qualified name "com.foo.mydomain.SomeEntity:someProperty" has changed name to "com.foo.mydomain.AnotherEntity:someProperty", so figure out that they are the same automatically. There are a number of simple rules like this that should be applicable as defaults. When they don't work it has to be possible to register custom rules, either on a per-property basis or a per-entity basis, or even coarser. > also if a piece of data is several revisions out of date then > would the migrations need to be composed in sequence? My guess is that it is best to go one revision at a time, i.e. composed migrations. But like you said, lots of scope for prototyping! As long as the basic mechanism is open-ended we can start simple and end with AI stuff :-) /Rickard _______________________________________________ qi4j-dev mailing list [email protected] http://lists.ops4j.org/mailman/listinfo/qi4j-dev
