nsfetchrequest

Can I apply multiple predicates to an NSFetchRequest? Would it be better to manually parse my results?

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Yes it’s possible. You’re looking for compound predicates and here’s an example with AND predicates: NSPredicate *compoundPredicate = [NSCompoundPredicate andPredicateWithSubpredicates:[NSArray of Predicates]]; You can also use notPredicateWithSubpredicates and orPredicateWithSubpredicates depending on your needs. Link to documentation https://developer.apple.com/documentation/foundation/nscompoundpredicate

Core data, how to get NSManagedObject’s ObjectId when NSFetchRequest returns NSDictionaryResultType?

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Yes you can, using the very nifty but badly-documented NSExpressionDescription class. You need to add a properly-configured NSExpressionDescription object to the array of NSPropertyDescription objects you set via setPropertiesToFetch: for your NSFetchRequest. For example: NSExpressionDescription* objectIdDesc = [[NSExpressionDescription new] autorelease]; objectIdDesc.name = @”objectID”; objectIdDesc.expression = [NSExpression expressionForEvaluatedObject]; objectIdDesc.expressionResultType = NSObjectIDAttributeType; myFetchRequest.propertiesToFetch = [NSArray arrayWithObjects:objectIdDesc, anotherPropertyDesc, … Read more

SwiftUI View and @FetchRequest predicate with variable that can change

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had the same problem, and a comment of Brad Dillon showed the solution: var predicate:String var wordsRequest : FetchRequest<Word> var words : FetchedResults<Word>{wordsRequest.wrappedValue} init(predicate:String){ self.predicate = predicate self.wordsRequest = FetchRequest(entity: Word.entity(), sortDescriptors: [], predicate: NSPredicate(format: “%K == %@”, #keyPath(Word.character),predicate)) } in this example, you can modify the predicate in the initializer.

CoreData get distinct values of Attribute

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You should use the backing store to help you get distinct records. If you want to get an array with just John, Betty, Edward here’s how you do it: NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:@”MyEntity”]; NSEntityDescription *entity = [NSEntityDescription entityForName:@”MyEntity” inManagedObjectContext:self.managedObjectContext]; // Required! Unless you set the resultType to NSDictionaryResultType, distinct can’t work. // All objects … Read more

How to get Core Data object from specific Object ID?

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You want: -(NSManagedObject *)existingObjectWithID:(NSManagedObjectID *)objectID error:(NSError **)error Fetches the object from the store that has that ID, or nil if it doesn’t exist. (Be aware: there are two methods on NSManagedObjectContext with similar-seeming names that tripped me up. To help keep them straight, here’s what the other two do: -(NSManagedObject *)objectWithID:(NSManagedObjectID *)objectID …will create a … Read more

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)