CODEWITHSUNDEEP
iosswiftcore-data
Adrian
Adrian

Reputation: 20058

Items are not added to Core Data when saving context

I am trying to build a Core Data app and I am using some code based on this book.

To simplify code I have something like this:

class City: NSManagedObject {
    @NSManaged public private(set) var name: String
    @NSManaged public private(set) var population: Int

    public static func insert(context: NSManagedObjectContext, name: String, population: Int) -> City {

        let city: City = context.insertObject()
        city.name = name
        city.population = population

        return city
    }
}


extension NSManagedObjectContext {
    public func insertObject<A: NSManagedObject>() -> A {
        guard let obj = NSEntityDescription.insertNewObjectForEntityForName("City", inManagedObjectContext: self) as? A else {
            fatalError("Wrong object type")
        }

        return obj
    }

    public func saveOrRoleback() -> Bool {

        do {
            try save()
            return true
        } catch {
            rollback()
            return false
        }
    }

    public func performChanges(block: () -> ()) {

        performBlockAndWait {
            block()
            print(self.saveOrRoleback())
        }
    }
}


func addCity() {
    self.context.performChanges {
        City.insert(self.context, name: self.name.text!, amount: Int(self.population.text!))
    }
}

When I add a new city, and save() is called inside saveOrRollback() method on the context, I don't get any error, it will return true.
But there is no data added. I tried to check the sql file and is empty.

Being new to Core Data can someone point me on where to look for issues ? I was expecting to get an error or something when saving, but everything seems to be normal, but the data base is empty all the time.

edit: - added core data setup

public func createContext() -> NSManagedObjectContext {

    let context = NSManagedObjectContext(concurrencyType: .MainQueueConcurrencyType)
    context.persistentStoreCoordinator = createStoreCoordinator()

    return context
}

private func createStoreCoordinator() -> NSPersistentStoreCoordinator {

    let psc = NSPersistentStoreCoordinator(managedObjectModel: model.managedObjectModel)

    try! psc.addPersistentStoreWithType(model.storeType.type, configuration: nil, URL: model.storeURL, options: nil)

    return psc
}

// Main VC
override func viewDidLoad() {
    super.viewDidLoad()

    let model = CoreDataModel(modelName: modelName, modelBundle: modelBundle!, storeType: .SQLite(DocumentsDirectoryURL()))
    let factory = CoreDataFactory(model: model)

    context = factory.createContext()

    self.todayViewController = storyboard?.instantiateViewControllerWithIdentifier("TodayViewController") as! TodayViewController
    self.todayViewController.context = context
}

edit 2: - sql debug after adding data

-06-18 22:31:15.042 Savings+[1100:39698] CoreData: sql: BEGIN EXCLUSIVE
2016-06-18 22:31:15.043 Savings+[1100:39698] CoreData: sql: SELECT Z_MAX FROM Z_PRIMARYKEY WHERE Z_ENT = ?
2016-06-18 22:31:15.043 Savings+[1100:39698] CoreData: sql: UPDATE Z_PRIMARYKEY SET Z_MAX = ? WHERE Z_ENT = ? AND Z_MAX = ?
2016-06-18 22:31:15.043 Savings+[1100:39698] CoreData: sql: COMMIT
2016-06-18 22:31:15.045 Savings+[1100:39698] CoreData: sql: BEGIN EXCLUSIVE
2016-06-18 22:31:15.045 Savings+[1100:39698] CoreData: sql: INSERT INTO ZTRANSACTION(Z_PK, Z_ENT, Z_OPT, ZAMOUNT, ZDATE, ZNAME, ZTYPE) VALUES(?, ?, ?, ?, ?, ?, ?)
2016-06-18 22:31:15.045 Savings+[1100:39698] CoreData: sql: COMMIT
2016-06-18 22:31:15.046 Savings+[1100:39698] CoreData: sql: pragma page_count
2016-06-18 22:31:15.046 Savings+[1100:39698] CoreData: annotation: sql execution time: 0.0003s
2016-06-18 22:31:15.046 Savings+[1100:39698] CoreData: sql: pragma freelist_count

Upvotes: 2

Views: 536

Answers (1)

pbasdf
pbasdf

Reputation: 21536

As discussed in comments/chat:

  1. Remember that the default journal mode for CoreData SQLite databases uses WAL mode, so you need to ensure any sql reader recognises those files. It's generally easier to use a fetch in your code than to read the sqlite files directly.
  2. Try using SQLDebug mode to see what is actually being read/written from/to sqlite.
  3. In this case, it transpired that you had a default predicate on your fetch request which excluded all the objects you have saved; removing the predicate shows that the data is there and your save is working correctly.

Upvotes: 1

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