Here is the situation, When I fetched mails from server, I do insert command. But that cause duplicate in my folders. So that should be fixed otherwise there are lots of duplicate mail in my INBOX.
Duplicate data base on CoreData
When receiving new data, I just do insertNewObjectForEntityForName function, Here is a wrong code:
- (NSManagedObject *)createManagedObjectOfClass:(Class)clazz{
if(![clazz isSubclassOfClass:NSManagedObject.self]){
return nil;
}
NSString *className = NSStringFromClass(clazz);
NSManagedObject *object = [NSEntityDescription insertNewObjectForEntityForName:className inManagedObjectContext:self.context];
return object;
}
// ...
- (CYMail *)createMailWithMessage:(MCOIMAPMessage *)message folder:(CYFolder *)folder{
CYMail *mail = (CYMail *)[self createManagedObjectOfClass:CYMail.self];
// ...
}
And that is the reason why I always get duplicate data. So I fixed it:
- (CYMail *)createMailWithMessage:(MCOIMAPMessage *)message folder:(CYFolder *)folder{
CYMail *mail;
NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"CYMail"];
request.predicate = [NSPredicate predicateWithFormat:@"uid = %@", @(message.uid)];
NSError *error;
NSArray *matches = [self.context executeFetchRequest:request error:&error];
if (!matches || [matches count] > 1) {
NSLog(@"Multiple copies of unique item detected in the document");
} else if (![matches count]){
mail = (CYMail *)[self createManagedObjectOfClass:CYMail.self];
// ...
} else {
mail = [matches lastObject];
}
return mail;
}
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