iphone - Isn't using lightweight migration with dozens of updates going to kill performance? -

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It seems that I notice that I should keep the entire stack of model versions while updating the update. I'm not sure what happened if someone has version 1.0 with population data, and then updates version 5.0 without any version. Therefore, migration must also know what it was like a long ago data model. Or maybe it does not work at all, know what.

However, after some changes I had a choice of 25 data models where the previous one was the current version. So, what do I think, that the store coordinator will have a lot of work to run on these versions and the differences, phase-by-step will be found. Is not it suck? Is there any action?

If a user is moving from version 1 to version 5, then the core data attempt will be that one near.

Core data has no concept of "version 1" and "version 5", it only understands the source and destination model. When a user loads your "version 1", the core data finds the source model in your bundle Core data will also determine the destination based on the "current" model. From there it tries to migrate.

So when you make a new edition, you test every possible migration of the Essential test to insure if they do not work with themselves Put that in mapping model for migration.

Therefore there is no performance problem because the core data will only display one migration.


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