Given an entity with an attribute firstName, Core Data automatically generates firstName, setFirstName:, primitiveFirstName, and setPrimitiveFirstName.
The primary use of primitive accessors is to prevent key-value observing notifications from being sent when you change a value.
Sometimes you do not want such notifications sent because they have quite a bit of overhead. E.g. when importing large sets of data or when you use a transitory value to alter a persisted value.
In my opinion,
You could override the awakeFromInsert method to set a default value for this property;
Every time you insert object into managedObjectContext,
CoreData framework will call awakeFromInsert method automatically.
And in this method,you should use primitive accssor to set the default value.
For example,there is a property dueDate in the category’s .h file,
u can define primitiveDueDate property in the subclass of NSManagedObject.
And add @dynamic primitiveDueDate in .m file.
show u the code:
// a subclass of NSManagedObject//.h file
@interface Task : NSManagedObject@property (nonatomic, strong) NSDate *primitiveDueDate;@end//.m file
@implementation Task@dynamic primitiveDueDate;- (void)awakeFromInsert{
[super awakeFromInsert]; NSDate *defaultDate = [NSDate dateWithTimeIntervalSinceNow:***]; // 3 days self.primitiveDueDate = defaultDate;
}@end// category file contains a property named dueDate@interface Task (CoreDataProperties)@property (nullable, nonatomic, retain) NSDate *dueDate;@end
References:
http://stackoverflow.com/questions/7427373/what-are-the-primitive-accessors-for-in-core-data
Caution (infinite loop):
http://stackoverflow.com/questions/14150654/kvo-core-data-and-primitive-accessors
