Check if value is in sqlite database before adding

Question

I am trying to preload some values into a database from a .csv file, but if they already exist then skip them. I am able to successfully parse the csv file then have the following function to check if they exist in the database:

func GetPreloadedDriverExists(manufacturer: String, model: String, size: Float, impedance: Int) -> Bool
{
    //1
    let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
    let managedContext = appDelegate.managedObjectContext!

    //2
    let fetchRequest = NSFetchRequest(entityName:"Drivers")
    fetchRequest.propertiesToFetch = ["size"]
    fetchRequest.returnsObjectsAsFaults = false
    fetchRequest.predicate = NSPredicate(format: "(manufacturer MATCHES %@) AND (model MATCHES %@) AND (#size == %@) AND (impedance == %@) AND (isRemovable == FALSE)", "\(manufacturer)", "\(model)", "\(size)", "\(impedance)")

    //3
    var error: NSError?

    let fetchedResults:NSArray = (managedContext.executeFetchRequest(fetchRequest, error: &error))!

    return fetchedResults.count == 0 ? false : true
}

The first time through this return false as I would expect for all entries, but when I open the sqlite file on the device, it is blank.

Here is the loop I am using to add the entries into the database.

if let managedObjectContext = self.managedObjectContext {
     for item in items {
     // Check if driver already exists in database, if not add it.
          if(!GetPreloadedDriverExists(item.manufacturer, model: item.model, size: (item.size as NSString).floatValue, impedance: (item.impedance as NSString).integerValue))
          {
               println("Value does not exist")
               let menuItem = NSEntityDescription.insertNewObjectForEntityForName("Drivers", inManagedObjectContext: managedObjectContext) as! Drivers
                        menuItem.manufacturer = item.manufacturer
                        menuItem.model = item.model
                        menuItem.size = (item.size as NSString).floatValue
                        menuItem.impedance = (item.impedance as NSString).integerValue

                if managedObjectContext.save(&error) != true {
                     println("insert error: \(error!.localizedDescription)")
                }
           }
      }
 }

Update #1 It appears that the information is saving somewhere, but when I save the container from the device and view the package contents, the sqlite file doesn't have my information in it, but when I run it in the debugger, it says all of the information is there.

Thank you for the help and any feedback.

score 0 · Accepted Answer · edited May 23 '17 at 12:21

0

I was able to find my answer here. It doesn't populate it straight to the sqlite file, it uses write ahead logging by default. Once I opened it with a database browser, all the data was merged and showed up in the sqlite file.

I then found how to disable the write ahead logging here, which resolved my issue and populated the .sqlite file automatically.

edited May 23 '17 at 12:21

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answered Jun 29 '15 at 20:24

Ian Oswald

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Check if value is in sqlite database before adding

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