Re: CoreData database sharing and migration
Re: CoreData database sharing and migration
- Subject: Re: CoreData database sharing and migration
- From: Tobias Jordan <email@hidden>
- Date: Wed, 17 Mar 2010 22:59:45 +0100
Hello Ben,
Thanks a lot for responding! My problem is as follows: The database
which is currently a non-document based core data SQLite one is
normally stored in the local User Library of the user. (/Users/user/
Library/Application Support/MyApp/database.db
But there are cases in which two (or more) different physical machines
must have access to the database. For example two designers working on
a project and they both need the same database so they can share their
results. This means they create a new database on their server and
link my app to this database.
As you've said, is there a way the data can be always immediately
written to disk so there's no 'last writer wins'?
I am not using NSDocument based techniques -- it is really just one
core data DB.
Thank you!
Regards,
Tobias
On Mar 17, 2010, at 10:29 PM, Ben Trumbull wrote:
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
_______________________________________________
Cocoa-dev mailing list (email@hidden)
Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden