If you have NSData for the image file, then you can guess at the content type by looking at the first byte: + (NSString *)contentTypeForImageData:(NSData *)data { uint8_t c; [data getBytes:&c length:1]; switch (c) { case 0xFF: return @”image/jpeg”; case 0x89: return @”image/png”; case 0x47: return @”image/gif”; case 0x49: case 0x4D: return @”image/tiff”; } return … Read more
Here’s the best way (and doesn’t require SQL knowledge): Create a quick Core Data iPhone app (Or even Mac app) using the same object model as your List app. Write a few lines of code to save the default managed objects you want to the store. Then, run that app in the simulator. Now, go … Read more
The solution is simple, just use the CascadeType.MERGE instead of CascadeType.PERSIST or CascadeType.ALL. I have had the same problem and CascadeType.MERGE has worked for me. I hope you are sorted.
Either way will add an entity to a PersistenceContext, the difference is in what you do with the entity afterwards. Persist takes an entity instance, adds it to the context and makes that instance managed (i.e. future updates to the entity will be tracked). Merge returns the managed instance that the state was merged with. … Read more