清空核心数据NSSet(多个关系)

Question

如果我需要以编程方式清空Core Data自动创建的NSSet(多个关系),我该怎么办？像这样的东西？

[self willChangeValueForKey:@"MyRelationship"];

[[self MyRelationship] release];
[self MyRelationship] = [NSSet alloc] init];

[self didChangeValueForKey:@"MyRelationship"];

不确定它是否正确...谢谢

Answer 1

[[self mutableSetValueForKey:@"MyRelationship"] removeAllObjects];

出于某种原因,我永远无法让"级联"删除规则起作用,所以当我想要删除对象时,我必须遍历集合并调用[self.managedObjectContext deleteObject:obj],否则我将得到验证错误,如果关系被定义为需要.