在 coredata 中保存对象时出错

Posted 2023-02-24

【中文标题】在 coredata 中保存对象时出错

【英文标题】：Error while saving object in coredata

【发布时间】：2011-11-09 19:41:12

【问题描述】：

这是我的代码：

- (IBAction) saveData

    NSLog(@"saveData");
    [self dismissKeyboard];
    Fugitive *job = (Fugitive *)[NSEntityDescription insertNewObjectForEntityForName:@"Fugitive" inManagedObjectContext:managedObjectContext];
    job.name = txtName.text;



    NSError *error;

    // here's where the actual save happens, and if it doesn't we print something out to the console
    if (![managedObjectContext save:&error])
    
        NSLog(@"Problem saving: %@", [error localizedDescription]);
    

    // **** log objects currently in database ****
    // create fetch object, this object fetch's the objects out of the database
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"Fugitive" inManagedObjectContext:managedObjectContext];
    [fetchRequest setEntity:entity];
    NSArray *fetchedObjects = [managedObjectContext executeFetchRequest:fetchRequest error:&error];

    NSURL *storeURL = [[NSBundle mainBundle] URLForResource:@"iBountyHunter" withExtension:@"momd"];

    id globalStore = [[managedObjectContext persistentStoreCoordinator] persistentStoreForURL:storeURL];


    [managedObjectContext assignObject:job toPersistentStore:globalStore];

    for (NSManagedObject *info in fetchedObjects)
    
        NSLog(@"Job Name: %@", [info valueForKey:@"name"]);

    
    [fetchRequest release];
[self.navigationController dismissModalViewControllerAnimated:YES];

在控制台中我收到此错误：保存时出现问题：操作无法完成。 （可可错误 1570。） 新对象在 tableview 中创建，但未保存，因此在重新启动应用程序时，该对象消失

【问题讨论】：

您的核心数据堆栈中可能存在配置问题。在您设置模型、持久存储和上下文的位置发布代码。此外，如果您已将上下文配置为已有商店并且您的应用只有一个商店，则无需执行 assignObject:toPersistentStore:。

我已经把代码贴出来了，放在这里太长了

【参考方案1】：

- (void)saveContext


    NSError *error = nil;
    NSManagedObjectContext *managedObjectContext = self.managedObjectContext;

    if (managedObjectContext != nil)
    
        if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error])
        
         NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
            abort();
         
    



- (NSManagedObjectContext *)managedObjectContext

    if (__managedObjectContext != nil)
    
        return __managedObjectContext;
    

    NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
    if (coordinator != nil)
    
        __managedObjectContext = [[NSManagedObjectContext alloc] init];
        [__managedObjectContext setPersistentStoreCoordinator:coordinator];
    
    return __managedObjectContext;


- (NSManagedObjectModel *)managedObjectModel

    if (__managedObjectModel != nil)
    
        return __managedObjectModel;
    
    NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"iBountyHunter" withExtension:@"momd"];
    __managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];    
    return __managedObjectModel;


- (NSPersistentStoreCoordinator *)persistentStoreCoordinator

    if (__persistentStoreCoordinator != nil)
    
        return __persistentStoreCoordinator;
    

    NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"iBountyHunter.sqlite"];

    NSError *error = nil;

    NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption, [NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption, nil];


    __persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
    if (![__persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:options error:&error])
    



    __persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
    if (![__persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:options error:&error])
    
               NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
        

    return __persistentStoreCoordinator;

【讨论】：

很高兴给出一些解释以及一大段旧代码！

这是解决方案，还是更多问题？