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You only do additive changes. Only add columns etc. never remove them ... until all your old application code is no longer running.
by david422 4y ago
You only do additive changes. Only add columns etc. never remove them ... until all your old application code is no longer running.
- naasking 4y agoAnd you have to weaken your schema to allow nulls for the duration that old and new code are both running (and possible foreign key constraint failures).
- petargyurov 4y agoThanks. I thought it would be something... smarter. Not sure I like that, seems to come with a lot of caveats.
- xani_ 4y ago"smarter" means more code and that's rarely more maintainable. It's what you have to do if you want less downtime. Normally it shouldn't span much more than 2-3 versions of application and it's rare that the annoying kind (say writing same data to "old" and "new" column) happens.
- outworlder 4y ago> until all your old application code is no longer running. Or until it's been disabled by feature flags.