Question

这是我的NSBatchUpdateRequest：

    let batchUpdateRequest = NSBatchUpdateRequest(entityName: "WLItem")
    batchUpdateRequest.predicate = NSPredicate(format: "source != rt")
    batchUpdateRequest.propertiesToUpdate = ["position": 2]
    batchUpdateRequest.resultType = NSBatchUpdateRequestResultType.UpdatedObjectsCountResultType

    do {
        let batchUpdateResult = try NSManagedObjectContext.MR_defaultContext().executeRequest(batchUpdateRequest) as! NSBatchUpdateResult
    } catch {
        print("error: \(error)")
    }

控制台上的

输出是：

错误：NilError

有什么问题？这是XCode7的问题吗？我是第一次与NSBatchUpdateRequest合作，所以我不知道之前是否是这样的。对我而言，代码应该可行。

Answer 1

您必须刷新managedContextObject才能更新数据库。我创建了一个函数，其中使用NSBatchUpdateRequest来更新数据库。以下是功能： -

 let managedContext = SharedInstance.appDelegate?.persistentContainer.viewContext


func updateDataFromTable(tableName:String, idOfPaticularTable ID:String, updatedDict:Dictionary<String, String>, success:@escaping (_ response:Bool)-> Void, failure:@escaping (_ error: Error?) -> Void) {

    let batchRequest = NSBatchUpdateRequest(entityName: tableName)
    let predicate = NSPredicate(format: "id == %@", ID)

    batchRequest.predicate = predicate
    batchRequest.propertiesToUpdate = updatedDict

    batchRequest.resultType = .updatedObjectIDsResultType
    do {
        // Execute Batch Request
        let batchUpdateResult = try managedContext?.execute(batchRequest) as! NSBatchUpdateResult

        // Extract Object IDs
        let objectIDs = batchUpdateResult.result as! [NSManagedObjectID]

        for objectID in objectIDs {
            // Turn Managed Objects into Faults
            let managedObject = managedContext?.object(with: objectID)
            managedContext?.refresh(managedObject!, mergeChanges: false)
        }
        success(true)
    } catch let error as NSError {
        print(error)
        failure(error)
    }
}

struct SharedInstance {

   static let appDelegate = UIApplication.shared.delegate as? AppDelegate

   static let employeetable = "EmployeeModel"
}

Answer 2

我在项目中遇到的同样问题。以下解决方案为我工作。试试这个

        let batchRequest = NSBatchUpdateRequest(entityName: "Card") 
        let predicate = NSPredicate(format: "set == %@", set)

        batchRequest.predicate = predicate
        batchRequest.propertiesToUpdate = [ "count" : 54 ] 

        batchRequest.resultType = .UpdatedObjectsCountResultType
        do {
            try self.managedObjectContext.executeRequest(batchRequest) as! NSBatchUpdateResult
        } catch _ {
        }

NSBatchUpdateRequest在Swift中引发错误

2 个答案: