我有一个父母实体,必须抚养孩子。 如果我命令父母一方拥有财产(例如姓名),所有物品都会被罚款。 但是,如果我尝试这样做的话:
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"child.@count" ascending:NO];
它没有工作。 我也试图补充。
[fetchRequest setRelationshipKeyPathsForPrefetching:[NSArray arrayWithObject:[entityProperties objectForKey:@"child"]]];
但它也没有工作。
我允许用手法进行分类,或者我是否需要增加财产,每增加一名儿童时更新财产?
假设你正在使用一种油罐;不能通过<条码>@count进行分类。 由于在“目标”一级解决了这一问题,而<代码>NSSortDescriptor上
如果你使用双轨或内层储存类型,那么计值就应当进行罚款,因为它们只能作为物体进入。
I have a have a number of calendars, which each have a number of events. I would like to find all the events for a calendar where date > x. My method signature looks like this -(NSArray*)...
I m having some trouble with a recursive relationship in core data. I ve got a managed object called a "SearchCategory", and that category can have "Categories" and it can also have a "Category." In ...
I have a string of data in a plist, which I ve got to display, hierarchically like this: Menu>Chapter>SubChapter>item>item details This might be super simple, in my initial menu, how would I have ...
I m a new iPhone developer (of about 4 months or so) who is starting to look at Core Data. In the "Beginning iPhone 3 Development" book by Dave Mark it mentions that the main difference between ...
When I generate my classes from CoreData entities I get generated methods @interface Site (CoreDataGeneratedAccessors) - (void)addSearchesObject:(Search *)value; - (void)removeSearchesObject:(Search *...
I am one of the great unwashed masses of .NET developers keen to try their hands at Mac OS X development. At the moment I am trying to figure out the various elements of Cocoa and getting a bit stuck ...
我想将核心数据作为输入数据库服务器更大数据集的切身。
In CoreData, if I want to limit the returned resultset to 100, is it enough to just set the fetch limit to 100, or do I need to set the fetch batch size to 100 as well?