Learning route:
Core Data tutorial for ioscore
Data utility tutorialcore
Data programming guid
Code: coredatabooksCore
Data model versioning and data migration programming guideatomic
Store programming topicsincremental
Store programming guide
Xcode tools for core data
Xcode mapping tool for core data
Cocoa bindings programming topics
??? : To implement the effect of some select fields, use: nsexpression's expressionforkeypath: And nsexpressiondescription?
[Fetchrequest setpropertiestofetch: [nsarray arraywithobject: expressiondescription];
Context-‐- ‐> coordinator-‐- ‐> Model
1. Managed Object Model
Is an object representation of a schema that describes
Your Database
Is a collection of Entity description objects (instances of nsentitydescription ).
2. A Persistent object store represents an external store (File) of persisted data
When you fetch records, core data retrieves results from all of them (unless you specify which store you're interested in ).
3. A managed object is
Object Representation of a record in a table in a database
A managed object is associated with an Entity description (an instance of nsentitydescription) that
Provides metadata about the object (including the name of the entity that the object represents and the names of its attributes and Relationships)
4. The managed object context manage
A collection of managed objects. These objects form a group of related model objects that represent an internally consistent view of one or more persistent stores.
5. An entity can be used to store different stores .. you specify the store for an object using the nsmanagedobjectcontext method, assignobject: topersistentstore :.
Transient properties are properties that you define
As part of the model, but which are not saved to the persistent store as part of an entity instance's data.
An attribute is optional-that is, it is not required to have a value
Fetched properties represent weak, one-way relationships
Cross stores.
Relationships represent to-specific relationship cannot be cross stores.
Faulting: a managed object may be a "fault"-an object whose property values have not yet been loaded from the external
Store
When you fetch a managed object, core data does not automatically fetch data for other objects to which it has relationships
