Saving to CoreData in a loop - ios

Question

I have a list of json objects that I want to write into CoreData. Json objects are coming from API. I have a method to Upsert a data into CoreData. The code for that is the following.
public class func upsertSetting (resultsArr : NSArray, settingTypeId: Int, countryId: Int) {
if let moc = CoreDataHelper().managedObjectContext {
var settings : [Setting]
settings = resultsArr as [Setting]
var existingSettings : [SettingCoreDataModel]?
existingSettings = fetchAllSettings(settingTypeId, countryId: countryId)
for result in settings {
var key = result.key
var value = result.value
if (value == nil)
{
value = ""
}
var id = result.id
var settingTypeId = result.settingTypeId
var countryId = result.countryId
var settingCoreData: [SettingCoreDataModel]?
var existingSetting: SettingCoreDataModel?
if(existingSettings? == nil){
existingSetting = nil
}
else{
settingCoreData = filter(existingSettings!) { (e:SettingCoreDataModel) in e.key == key }
if(settingCoreData? != nil && settingCoreData?.count > 0){
existingSetting = settingCoreData?.first
}
}
if(existingSetting == nil){
SettingCoreDataModel.createInManagedObjectContext(moc, key: key!, value: value!, id: id!, settingTypeId: settingTypeId!, countryId: countryId!)
}
else if(existingSetting?.value != value!){
existingSetting?.value = value!
save()
}
}
}
}
public class func save() {
var error : NSError?
if !CoreDataHelper().managedObjectContext!.save(&error) {
println("Could not save \(error), \(error?.userInfo)")
}
}
fetchAllSettings looks like this:
public class func fetchAllSettings (settingTypeId: Int, countryId: Int) -> [SettingCoreDataModel]?
{
let fetchRequest = NSFetchRequest(entityName: "SettingCoreDataModel")
let predicate = NSPredicate(format: "settingTypeId == %d AND countryId == %d", settingTypeId, countryId)
fetchRequest.predicate = predicate
if let fetchResults = CoreDataHelper().managedObjectContext!.executeFetchRequest(fetchRequest, error: nil) as? [SettingCoreDataModel] {
return fetchResults
}
else{
return []
}
}
And here is the SettingCoreDataModel with createInManagedObjectContext :
public class SettingCoreDataModel: NSManagedObject {
#NSManaged var key: String
#NSManaged var value: String
#NSManaged var id: NSNumber
#NSManaged var settingTypeId: NSNumber
#NSManaged var countryId: NSNumber
class func createInManagedObjectContext(moc: NSManagedObjectContext, key: NSString, value: NSString, id: int, settingTypeId: int, countryId: int) -> SettingCoreDataModel {
let newItem = NSEntityDescription.insertNewObjectForEntityForName("SettingCoreDataModel", inManagedObjectContext: moc) as? SettingCoreDataModel
newItem?.key = key
newItem?.value = value
newItem?.id = id
newItem?.settingTypeId = settingTypeId
newItem?.countryId = countryId
return newItem!
}
}
My problem is, when I call createInManagedObjectContext it does not seem to be saving into CoreData. I couldn't figure the issue and I'm fairly new to Swift and XCode
Edit: One thing I forgot to mention is that, I'm trying to create a plugin with this. All my code is in Pod but my data model is in example project. I'm not sure if that makes any difference to that, but while fetching and everything it seems to be working fine.
Using save() didn't help either by the way.
I call upsertSetting on application didFinishLaunchingWithOptions. After that, on my first view I try to get a single record by key and use it on the table view:
var textColorSetting: Setting?
override func viewDidLoad() {
super.viewDidLoad()
textColorSetting = SettingCoreData.fetchSetting("text_color", countryId: 3)
}
Table cells:
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell: UITableViewCell = tableView.dequeueReusableCellWithIdentifier(kCellIdentifier) as UITableViewCell
textColorSetting = SettingCoreData.fetchSetting("text_color", countryId: 3)
var textColor = textColorSetting?.value
if (textColor? == nil){
textColor = "#ff00ff"
}
let color = SettingCoreDataModel.hexStringToUIColor(textColor!)
cell.textLabel?.textColor = color
}
Fetching single setting:
public class func fetchSetting(key : NSString, countryId: Int) -> Setting? {
let fetchRequest = NSFetchRequest(entityName: "SettingCoreDataModel")
var existingSetting: SettingCoreDataModel?
let predicate = NSPredicate(format: "key == %# AND countryId == %d", key, countryId)
fetchRequest.predicate = predicate
var error: NSError?
if let fetchResults = CoreDataHelper().managedObjectContext!.executeFetchRequest(fetchRequest, error: &error) as? [SettingCoreDataModel] {
println(fetchResults.count)
if (!fetchResults.isEmpty && fetchResults.count > 0) {
existingSetting = fetchResults.first!
var setting: Setting?
setting?.id = existingSetting?.id as? Int
setting?.key = existingSetting?.key
setting?.value = existingSetting?.value
setting?.settingTypeId = existingSetting?.settingTypeId as? Int
setting?.countryId = existingSetting?.countryId as? Int
return setting
} else {
return nil
}
} else {
return nil
}
}
In here println(fetchResults.count) always prints 0. That's why I assume save() is not working.

Answer 1

In the case where you create a new setting, you need to invoke save (or better yet, take save out of the inside of the loop and just call it once after the loop)
if(existingSetting == nil){
SettingCoreDataModel.createInManagedObjectContext(moc, key: key!, value: value!, id: id!, settingTypeId: settingTypeId!, countryId: countryId!)
save() // this is missing
}
Some other observations and simplifications:
fetchAllSettings will always return a valid array (possibly empty) of settings, declare it as -> [SettingCoreDataModel] instead of declaring it as an optional:
public class func fetchAllSettings (settingTypeId: Int, countryId: Int) -> [SettingCoreDataModel]
var existingSettings = fetchAllSettings(settingTypeId, countryId: countryId)
having done that you can use the fact that first returns an optional to simplify the logic to find an existing setting to:
var existingSetting = existingSettings.filter({ (e:SettingCoreDataModel) in e.key == key }).first
To insure that value always has a valid value, so you don't have to worry about unwrapping it, use nil checking:
var value = result.value ?? ""