Re: [Leopard] Core Data and model changes regarding indexing
Re: [Leopard] Core Data and model changes regarding indexing
- Subject: Re: [Leopard] Core Data and model changes regarding indexing
- From: Aurélien Hugelé <email@hidden>
- Date: Thu, 01 Nov 2007 16:17:59 +0100
Hi list,
In a previous post [Re: Core data model configuration & Leopard],
mmalc answered pretty precisely to a question regarding model changes,
and what is considered a change.
Has the *model* changed in any way? With the new versioning and
migration feature in 10.5, Core Data takes the following into account:
Core Data’s perspective on versioning is that it is only interested
in features of the model that affect persistence. This means that
for two models to be compatible:
• For each entity the following attributes must be equal: name,
parent, isAbstract, and properties.
className, userInfo, and validation predicates are not compared.
• For each property in each entity, the following attributes must
be equal: name, isOptional,isTransient, isReadOnly, for attributes
attributeType, and for relationshipsdestinationEntity, minCount,
maxCount, deleteRule, and inverseRelationship.
userInfo and validation predicates are not compared.
(see Core Data Model Versioning and Data Migration Programming Guide
> Versioning).
Not all this information is maintained in the store, but it *may* be
that you managed to get away with something on Tiger that isn't now
allowed on Leopard.
But I've seen no info about the "isIndexed" attributes migration.
I have model working on Tiger with no index placed on any attributes,
but now, I would like to index some attributes. How does it affect
models compatibility?
Is it managed by the migration manager ? is it safe to simply check
this checkbox in Xcode modeler?
Thanks.
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