Re: ERXMigrationDatabase and postUpgrade
Re: ERXMigrationDatabase and postUpgrade
- Subject: Re: ERXMigrationDatabase and postUpgrade
- From: Mike Schrag <email@hidden>
- Date: Sat, 11 Apr 2009 07:50:09 -0700
one is that your model will change over time and the constant you
refer to in migration0 might not exist in a month, so it would stop
compiling.
I _want_ the compiler error. I'd much rather get a compiler error
than a runtime error.
No you don't :)
Well, not for this at least ... the point of migrations is that things
change. if you ever delete a column from your database you would
break HISTORICAL state. this is the same reason why you can't touch
anything related to an EOModel inside your migration method, because
your EOModel and java files always only ever match LATEST state, but
you have to be able to migrate from old state that no longer matches
the latest models and java files. If you remove a column in version
3, you would break your version 1 where it existed, which is incorrect
-- you would be changing history. You have to be able to play back db
changes exactly as they were regardless of the current state of your
models.
ms
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