Question

I have an app with some stocks information for example and store it in CoreData. I have two entities Stock(name) and DailyStockData(date,number) and I store two years information for each stock entity. Then user can delete some Stock names in TableView.

In my - (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
I delete this Stock and DailyStockData cascade and save context then.

My save code looks like this

// Save the context.
NSError *error = nil;
if (![context save:&error])
{
    NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
    abort();
}

The problem is: when User deleting stocks fast – my app crashing. I understand that the reason is “abort” command when my device didn’t finish save previous deleting transaction and call to save it again.

So I have two questions here ^)
1. Is there any way to prevent this crash?
2. What is best practice to deal with context save error? May be I can try save it again and again rather than just abort.

The simplest solution is redesign application to save context at the “very” end – for example when my app change view or something but I want to know all possibilities.

Answer 1

You should NOT invoke “save” frequently, it’s bad for performance.

The “save” method let the CoreData actually save the modified data to your disk, it takes time if there are a lot of data need to be saved.

Just save once while your App is going to exit or going background is good enough.

If you worry about an unexpected crash will lose some data, you can invoke “save” when your users stop modifying data for a while or exited the edit view in your App. It depend on your decision, but just don’t save every time your data is changed.