after i add new data in core data collection it can't be saved (multiply validation error occured) - core-data

Question

The code bellow add to Core data issues, but after it added, I can't save with error (multiply validation error occured)
MySQLIXC *ixcDatabase = [[MySQLIXC alloc] init];
NSArray *destinationsForSaleList = [ixcDatabase destinationsForSaleList:carrier];
NSFetchRequest *request1 = [[[NSFetchRequest alloc] init] autorelease];
[request1 setEntity:[NSEntityDescription entityForName:#"DestinationsList"
inManagedObjectContext:managedObjectContext]];
for (NSDictionary *destinationsForSale in destinationsForSaleList) {
NSManagedObject *object1 = [NSEntityDescription
insertNewObjectForEntityForName:#"DestinationsList"
inManagedObjectContext:managedObjectContext];
NSLog(#"Moc: %#",managedObjectContext);
[object1 setValue:#"y" forKey:#"weAreSoldIt"];
// changeDate
NSString *chdate = [destinationsForSale objectForKey:#"chdate"];
NSDateFormatter *changeDate = [[[NSDateFormatter alloc] init] autorelease];
[object1 setValue:[changeDate dateFromString:chdate] forKey:#"changeDate"];
NSLog(#"Carrier :%# Destination name:%#",carrier, destinationsForSale);
//Country
[object1 setValue:[destinationsForSale objectForKey:#"country"] forKey:#"country"];
//rate
NSNumberFormatter *rate = [[[NSNumberFormatter alloc]init ]autorelease];
[object1 setValue:[rate numberFromString:[destinationsForSale objectForKey:#"price"]] forKey:#"rate"];
Unfortunately I can't fix a bug by the way which u propose bellow.
Bcs Entity DestinationList must have relations with Entity Carriers by project understanding.
That is how I try to fix it:
[objectDestinationList setValue:objectCarrier forKey:#"carrier"];
I was send to method my carrier object as object, but it doesn't work.
In this case, I don't know how is a way to fix it around. Bcs I see error, but don't see case why error is start.
Do u know a simple code to correct add relationships to Entity? All what I catch around internet is a core data book ,my Marcus Zarra and his very hard to understanding example. His showing a complex solution, I can understand it, but using programming style which not very easy for me at this moment (according my one month experience in cocoa programming ;)
Here is additional information: How I create Carrier instance. I have managedObjectContext, which I receive to class from AppDelegate.
NSFetchRequest *request = [[[NSFetchRequest alloc] init] autorelease];
[request setEntity:[NSEntityDescription entityForName:#"Carrier"
inManagedObjectContext:managedObjectContext]];
NSManagedObject *carrier = [managedObjectContext executeFetchRequest:request error:&error]
by the same way I prepare NSManagedObject for DestinationsList Entity.
After that I add all values to NSManagedObject for destinationsList, I have to make relationship between Carrer NSManagedObject and destinationsList. In this case I have trouble. Bellow is how I try to update relationship for Carrier entity:
NSSet *newDestSet = [NSSet setWithObjects:objectDestination,nil];
[objectCarrier setValue:newDestSet forKey:#"destinationsList"];
finally I have 2010-11-03 21:22:56.968 snow[20301:a0f] -[NSCFArray initialize]: unrecognized selector sent to instance 0x1c44e40
Bellow is my class interface deescription:
#interface InitUpdateIXC : NSObject {
NSInteger destinationType;
}
-(void) updateCarrierList:(NSManagedObjectContext *)managedObjectContext;
-(void)updateDestinationList:(NSManagedObjectContext *)managedObjectContext
forCarrier:(NSString *)carrierName
forCarrierObject:(NSManagedObject *)objectCarrier
destinationType:(NSInteger)destinationType;
#end
Yep, bellow in answer present correct model, but some different is here.
At first, i don't have separate class for Entity as u present in you model. My current class is just NSManagedObject
In second, relationship "carrier" is non-optional for Entity DestinationsList.
SOLUTION AND ERROR DESCRIPTION:
In case of trouble, what happened with my code:
When i try to add setValue forKey with back relationship from DestinationsList to Carrier, i forget that NSManagmentObject return every time array, not just object.
This is a reason why i receive error about array init problem.
Solution is not sent Carrier object to method, bcs for me was too hard to extract from array correct object without key value. I was using a predicate access to extract object to array and lastObject function to extract correct object from array. After that i set accroding value and everything working fine.
A solution not look like cocoa-style, so better way is refactor it in future, any suggestion wellcome.
Here is appropriate code:
NSFetchRequest *request = [[[NSFetchRequest alloc] init] autorelease];
[request setEntity:[NSEntityDescription entityForName:#"Carrier"
inManagedObjectContext:managedObjectContext]];
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"name =%#",carrierName];
[request setPredicate:predicate];
NSError *error = nil;
NSArray *currentCarriers = [managedObjectContext executeFetchRequest:request error:&error];
[objectDestination setValue:[currentCarriers lastObject] forKey:#"carrier"];

Answer 1

Try adding something like this for you 'save'
NSError *error = nil;
if (![managedObjectContext save:&error])
{
// Handle the error.
NSLog(#"Failed to save to data store: %#", [error localizedDescription]);
NSArray* detailedErrors = [[error userInfo] objectForKey:NSDetailedErrorsKey];
if(detailedErrors != nil && [detailedErrors count] > 0)
{
for(NSError* detailedError in detailedErrors)
{
NSLog(#" DetailedError: %#", [detailedError userInfo]);
}
}
else
{
NSLog(#" %#", [error userInfo]);
}
}
At least, then you can see what the multiple errors are. If you post those, someone may be able to offer more help.
One thought, though, is that there is something buggy about your data model - like non-optional attribute with no value, etc.
If you create NSManagedObject subclassed Carrier and DestinationsList, then in Carrier.h you should have some method declarations like this. (Assuming that Carrier to-many DestinationsList is called 'destinationsLists'.)
#interface Carrier (CoreDataGeneratedAccessors)
- (void)addDestinationsListsObject:(Run *)destinationsList;
- (void)removeDestinationsListsObject:(Run *)destinationsList;
- (void)addDestinationsLists:(NSSet *)destinationsLists;
- (void)removeDestinationsLists:(NSSet *)destinationsLists;
#end
Once these are declared, you should be able to add a DestinationsList to a Carrier with a line like this:
[myCarrier addDestinationsListsObject:myDestinationsList];
Not seeing your full data model, it is difficult to know what is happening and what would help fix it.
Do you have something like this for your model definition?