使用带有NSBatchDeleteRequest的NSFetchedResultsController

Question

我在使用NSBatchDeleteRequest后从NSFetchedResultsControllerDelegate获得准确更新时遇到问题,更改是作为更新类型而不是didChange委托方法上的删除类型.有没有办法让更改作为删除进入？(我有不同的删除与更新方案).

删除请求:(使用调用者提供的私有上下文)

fileprivate class func deletePeopleWith(ids: Set<Int>, usingContext context: NSManagedObjectContext) {

    let fr: NSFetchRequest<NSFetchRequestResult> = NSFetchRequest(entityName: "Person")

    var predicates: [NSPredicate] = []
    ids.forEach {

        predicates.append(NSPredicate(format: "id = %ld", $0))
    }

    fr.predicate = NSCompoundPredicate(orPredicateWithSubpredicates: predicates)

    let dr = NSBatchDeleteRequest(fetchRequest: fr)
    dr.affectedStores = context.parent?.persistentStoreCoordinator?.persistentStores

    do {

        try context.parent?.execute(dr)
        context.parent?.refreshAllObjects()
        print("Deleting person")

    } catch let error as NSError {

        let desc = "Could not delete person with batch delete request, with error: \(error.localizedDescription)"
        debugPrint(desc)
    }

}

结果是:

func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange anObject: Any, at indexPath: IndexPath?, for type: NSFetchedResultsChangeType, newIndexPath: IndexPath?) {

    DispatchQueue.main.async {

        let changeDesc = "Have change with indexPath of: \(indexPath), new index path of: \(newIndexPath) for object: \(anObject)"
        var changeType = ""
        switch type {

        case .delete:
            changeType = "delete"

        case .insert:
            changeType = "insert"

        case .move:
            changeType = "move"

        case .update:
            changeType = "update"

        }

        print(changeDesc)
        print(changeType)
    }

}

印刷:

Have change with indexPath of: Optional([0, 0]), new index path of: Optional([0, 0]) for object: *my core data object*
update

Answer 1

来自Apple的文档:

批量删除比在代码中自己删除Core Data实体运行得更快,因为它们在SQL级别的持久性存储本身中运行.作为此差异的一部分,持久性存储上实现的更改不会反映在当前内存中的对象中.

执行批量删除后,删除内存中已从持久性存储中删除的所有对象.

有关处理删除的对象,请参阅" 执行后更新应用程序"部分NSBatchDeleteRequest.