Validation for Core Data objects

This project provides a simple extension for the NSEntityDescription class in Core Data. If allows you to do some basic validation before creating NSManagedObjects.

Usage:

#import "NSEntityDescription+DLValidation.h"

// ...

- (void)foo {
    NSEntityDescription *entity = ...;
    NSDictionary *item = ...; // a provisional object from which we intend to build a proper NSManagedObject

    NSString *errorProp;
    ValidationError err = [entity validateWith:item errorProperty:&errorProp];

    if(err == ValidationErrorNone) {
        // no error. build an object
        NSManagedObjectContext *context = ...; 
        NSManagedObject *obj = [[NSManagedObject alloc] initWithEntity:entity insertIntoManagedObjectContext:context];
        [obj setValuesForKeysWithDictionary:item];
    }
    else if(err & ValidationErrorMissingValue) {
        NSLog(@"Error: User didn't enter the value for %@", errorProp);
    }
    else if(err & ValidationErrorWrongCardinality) {
        NSLog(@"Error: There are too few or to many items in relationship %@", errorProp);
    }
    else if(err & ValidationErrorMissingRelationship) {
        NSLog(@"Error: Nothing is selected for to-one relationship %@", errorProp);
    }
}

Contact

Bug reports and pull requests are welcome! Just write an e-mail or (preferred) open an issue on GitHub.