Question

我在保存核心数据时随机收到此错误

import Foundation
import CoreData
class CoreDataStack {
    private init() {

    }

    class func getContext () -> NSManagedObjectContext {
        return CoreDataStack.managedObjectContext
    }
    // MARK: - Core Data stack

    static var managedObjectContext: NSManagedObjectContext = {

        var applicationDocumentsDirectory: URL = {
            // The directory the application uses to store the Core Data store file. This code uses a directory named "com.cadiridris.coreDataTemplate" in the application's documents Application Support directory.
            let urls = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
            return urls[urls.count-1]
        }()

        var managedObjectModel: NSManagedObjectModel = {
            // The managed object model for the application. This property is not optional. It is a fatal error for the application not to be able to find and load its model.
            let modelURL = Bundle.main.url(forResource: "Thyssenkrupp", withExtension: "momd")!
            return NSManagedObjectModel(contentsOf: modelURL)!
        }()

        var persistentStoreCoordinator: NSPersistentStoreCoordinator = {
            // The persistent store coordinator for the application. This implementation creates and returns a coordinator, having added the store for the application to it. This property is optional since there are legitimate error conditions that could cause the creation of the store to fail.
            // Create the coordinator and store
            let coordinator = NSPersistentStoreCoordinator(managedObjectModel: managedObjectModel)
            let url = applicationDocumentsDirectory.appendingPathComponent("Thyssenkrupp.sqlite")
            var failureReason = "There was an error creating or loading the application's saved data."
            let options = [ NSMigratePersistentStoresAutomaticallyOption: true, NSInferMappingModelAutomaticallyOption:true ]
            do {
                try coordinator.addPersistentStore(ofType: NSSQLiteStoreType, configurationName: nil, at: url, options: options)
            } catch {
                // Report any error we got.
                var dict = [String: AnyObject]()
                dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data" as AnyObject?
                dict[NSLocalizedFailureReasonErrorKey] = failureReason as AnyObject?

                dict[NSUnderlyingErrorKey] = error as NSError
                let wrappedError = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict)
                // Replace this with code to handle the error appropriately.
                // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
                print("Unresolved error \(wrappedError), \(wrappedError.userInfo)")
                //abort()
            }

            return coordinator
        }()

        // Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.) This property is optional since there are legitimate error conditions that could cause the creation of the context to fail.
        let coordinator = persistentStoreCoordinator
        var managedObjectContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)
        managedObjectContext.persistentStoreCoordinator = coordinator
        return managedObjectContext
    }()

    // MARK: - Core Data Saving support

    class func saveContext () {
        DispatchQueue.main.async { 
            if managedObjectContext.hasChanges {
                do {
                    try managedObjectContext.save()
                } catch {
                    // Replace this implementation with code to handle the error appropriately.
                    // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
                    let nserror = error as NSError
                    print("Unresolved error \(nserror), \(nserror.userInfo)")
                    //abort()
                }
            }
        }

    }
}

过去3个月一切正常，但最近由于应用程序的变化，我必须调用大量的获取和保存请求，其中一些是在循环中，有些在我做了这些更改后关闭了这个错误。

以下是coredata manager的代码

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请提供任何有关此错误发生的建议

Answer 1

问题是经常将数据保存到CoreData，是的，您可以根据需要频繁地保存CoreData，但是如果您添加/删除/更新数据并以这种方式保存在循环中，则会通过控制台上的此错误进行操作此错误并非总是如此，但最好在循环完成后保存CoreData。由于在执行创建，更新，删除操作并且由于某种原因我们未保存CoreData应用崩溃/关闭的情况下，保存到核心数据很重要，因此从上次保存CoreData的那一刻起数据将丢失。保存到CoreData就像检查点一样，所有内容都已保存。因此，保存循环不是一种有效的方法。

如何修复尝试以coredata递归调用-save错误？

1 个答案: