相关疑难解决方法(0)

我需要为抽象基础对象创建复杂谓词.我想为不同的继承实体设置单独的谓词查询并关闭子实体类型,下面的示例是我想要做的,但是,我还没有找到引用实体名称或输入的方法谓词.

NSFetchRequest *request = [[NSFetchRequest alloc] init];
request.entity = [NSEntityDescription entityForName:@"MyCommonObjectBase" inManagedObjectContext:myContext];

NSPredicate *subclassAPredicate = [NSPredicate predicateWithFormat:@"someValue > %@ && entityName = %@", 100, @"SubclassA"];
NSPredicate *subclassBPredicate = [NSPredicate predicateWithFormat:@"someValue < %@ && entityName = %@", 50, @"SubclassB"];

request.predicate = [NSCompoundPredicate orPredicateWithSubpredicates:[NSArray arrayWithObjects:subclassAPredicate, subclassBPredicate, nil]];