StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PO
text
Body
copied!<p>I struggled with this for a little while myself. The real problem here is that the debugging you've got isn't showing you what the problem is. The reason for this is because CoreData will put an array of NSError objects in the "top level" NSError object it returns if there is more than one problem (This is why you see error 1560, which indicates multiple problems, and an array of error 1570s). It appears that CoreData has a handful of keys it uses to stash information in the error it returns if there is an issue that will give you more useful information (Such as the entity the error occurred on, the relationship/attribute that was missing, etc). The keys you use to inspect the userInfo dictionary can be found in <a href="http://developer.apple.com/documentation/Cocoa/Reference/CoreDataFramework/Miscellaneous/CoreData_Constants/Reference/reference.html" rel="noreferrer">the reference docs here</a>.</p> <p>This is the block of code I use to get reasonable output from the error returned during a save:</p> <pre><code> NSError* error; if(![[survey managedObjectContext] save:&error]) { NSLog(@"Failed to save to data store: %@", [error localizedDescription]); NSArray* detailedErrors = [[error userInfo] objectForKey:NSDetailedErrorsKey]; if(detailedErrors != nil && [detailedErrors count] > 0) { for(NSError* detailedError in detailedErrors) { NSLog(@" DetailedError: %@", [detailedError userInfo]); } } else { NSLog(@" %@", [error userInfo]); } } </code></pre> <p>It will produce output that tells you the fields that are in missing, which makes fixing the problem significantly easier to deal with.</p>

Querying!

Guidance

An individual column

Larger individual text columns get their own page to allow for proper reading.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload