coreData现有验证

Question

所以我正在使用 CoreData 填写申请表首先，我使用唯一名称和一些属性创建 "Shop"。在应用程序中，您可以编辑 "Shop"，我正在尝试通过 "shopName" 进行验证，以避免创建另一个具有相同名称的 "Shop"。我正在使用这个：

    -(BOOL)uniqueEntityExistsWithEnityName {

    BOOL returnValue = NO;

    NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Shop"];

    NSPredicate* predicate = [NSPredicate predicateWithFormat:@"shopName = [cd] %@", _shopName.text];

    NSSortDescriptor *shop = [[NSSortDescriptor alloc] initWithKey:@"shopName" ascending:YES];

    [request setSortDescriptors: @[shop]];
    [request setPredicate:predicate];

    NSError *error = nil;
    NSArray *matches = [self.managedObjectContext executeFetchRequest:request error:&error];

    NSLog(@"request = %@",predicate);

    if (!matches) {
        NSLog(@"Error: Couldn't execute fetch request %@", error);

    }
    else if([matches count] > 1) {

        NSString *existShop = [NSString stringWithFormat:@"Could Be Only One %@ Shop", _shopName.text];

        UIAlertView *exist = [[UIAlertView alloc]initWithTitle:@"Shop Exists in Your Records"
                                                       message:existShop
                                                      delegate:nil
                                             cancelButtonTitle:@"Ok"
                                             otherButtonTitles:nil];
        [exist show];

        NSLog(@"Error: Have more than %lu records",
              (unsigned long)[matches count]);
        returnValue = YES;
    }
    else {

        NSLog(@"%lu object in record", (unsigned long)[matches count]);

        [self oldShopDelete];
        [self checkShopPhoneNumber];

        editShop.shopName = _shopName.text;
        editShop.shopPhoneNumber = _shopPhoneNumber.text;
        editShop.shopSecondPhoneNumber = _shopSecondPhoneNumber.text;
        editShop.shopEmail = _shopEmail.text;
        editShop.shopNote = _shopNoteView.text;

        [super saveAndDissmiss];

        returnValue = YES;
    }
    return returnValue;
}

使用该代码，您仍然有机会保存另外一个具有相同名称的已编辑 "Shop"。但问题是 - 我无法在这之后制作 [matches count] = 1 我将没有机会编辑那个商店

也许还有另一种方法可以进行这种验证？

Answer 1

仅在实际首次设置或编辑名称时才检查名称冲突。

您还可以将当前商店传递给谓词以确保AND SELF != %@不会与正在编辑但名称未更改的现有商店匹配。

coreData现有验证

coreData existing validation

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uitextfield