re: CoreData database sharing and migration
re: CoreData database sharing and migration
- Subject: re: CoreData database sharing and migration
- From: Ben Trumbull <email@hidden>
- Date: Wed, 17 Mar 2010 14:29:33 -0700
> I am wondering whether it is possible to create a database in core
> data that can be opened by more than one application at the same time.
> It is currently impossible to handle one SQLite database with two
> instances of the same app. The problem is if user1 quits the app, the
> data is saved but user2's instance of the app doesn't recognize this
> file system change and just overwrites its version in memory. So the
> data from user1 is gone. Is there a way I can handle this?
>
> Second -- I am having more than two database versions now but still
> want to support my version 1.0 but the mapping model only allows one
> source model as well as only one target model. I would have to remove
> one version but that makes version 1.0 users' database unusable.
>
> Has anyone gotten something like this to work?
Yes, several Apple frameworks use Core Data databases from multiple processes simultaneously with a single user account and single physical machine.
Do you mean "more than one application simultaneously on more than one physical computer over NFS/AFP/SMB" ? Don't do that.
Or do you mean an NSDocument based application using Core Data & an SQLite store ? NSDocuments intentionally behave like TextEdit. Last writer wins, overwites everything. If so, you should be using a non-document based Core Data project template.
- Ben
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