Core Data 1-to-many relationship: List all related objects as section header in UITableView
- by Snej
Hi:
I struggle with Core Data on the iPhone about the following:
I have a 1-to-many relationship in Core Data. Assume the entities are called recipe and category. A category can have many recipes.
I accomplished to get all recipes listed in a UITableView with section headers named after the category.
What i want to achieve is to list all categories as section header, even those which have no recipe:
category1 <--- this one should be displayed too
category2
recipe_x
recipe_y
category3
recipe_z
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Recipe" inManagedObjectContext:managedObjectContext];
[fetchRequest setEntity:entity];
[fetchRequest setFetchBatchSize:10];
NSSortDescriptor *sortDescriptor1 = [[NSSortDescriptor alloc] initWithKey:@"category.categoryName" ascending:YES];
NSSortDescriptor *sortDescriptor2 = [[NSSortDescriptor alloc] initWithKey:@"recipeName" ascending:YES];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor1,sortDescriptor2, nil];
[fetchRequest setSortDescriptors:sortDescriptors];
NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:managedObjectContext sectionNameKeyPath:@"category.categoryName" cacheName:@"Recipes"];
What is the most elegant way to achieve this with core data?
