CODEWITHSUNDEEP
swiftcore-data
user6718553
user6718553

Reputation: 23

use of unresolved identifier 'entityDescription'

An error use of unresolved identifier 'entityDescription' is coming in my code. Even after a lot of failed attempts am unable to resolve it.

   import UIKit
import CoreData

class SwiftCoreDataHelper: NSObject {

class func directoryForDatabaseFilename()->NSString{
    return NSHomeDirectory().stringByAppendingString("/Library/Private Documents")
}


class func databaseFilename()->NSString{
    return "database.sqlite";
}


class func managedObjectContext()->NSManagedObjectContext{


    do { try NSFileManager.defaultManager().createDirectoryAtPath(SwiftCoreDataHelper.directoryForDatabaseFilename() as String, withIntermediateDirectories: true, attributes: nil) }
    catch {
        print("Error Creating Directory for DB")
    }
    //        NSFileManager.defaultManager().createDirectoryAtPath(SwiftCoreDataHelper.directoryForDatabaseFilename(), withIntermediateDirectories: true, attributes: nil, error: &error)

    let path:NSString = "\(SwiftCoreDataHelper.directoryForDatabaseFilename()) + \(SwiftCoreDataHelper.databaseFilename())"

    let url:NSURL = NSURL(fileURLWithPath: path as String)

    let managedModel:NSManagedObjectModel = NSManagedObjectModel.mergedModelFromBundles(nil)!

    let storeCoordinator:NSPersistentStoreCoordinator = NSPersistentStoreCoordinator(managedObjectModel: managedModel)

    do {
   try storeCoordinator.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil)
    }
    catch {
        print("Error: \(error)")
        }

    let managedObjectContext = NSManagedObjectContext(concurrencyType: NSManagedObjectContextConcurrencyType.MainQueueConcurrencyType)

    managedObjectContext.persistentStoreCoordinator = storeCoordinator

    return managedObjectContext


}

class func insertManagedObject(className:NSString, managedObjectConect:NSManagedObjectContext)->AnyObject{

    let managedObject:NSManagedObject = NSEntityDescription.insertNewObjectForEntityForName(className as String, inManagedObjectContext: managedObjectConect) as NSManagedObject

    return managedObject

}

class func saveManagedObjectContext(managedObjectContext:NSManagedObjectContext)->Bool{
    do {
        try managedObjectContext.save()
        return true
    } catch {
        return false
    }
}


class func fetchEntities(className:NSString, withPredicate predicate:NSPredicate?, managedObjectContext:NSManagedObjectContext)->NSArray{
    let fetchRequest:NSFetchRequest = NSFetchRequest()


    guard let entityDescription = NSEntityDescription.entityForName(className as String, inManagedObjectContext: managedObjectContext) else {
        //handle error here
        return 
    }

    fetchRequest.entity = entityDescription
    if let predicate = predicate {
        fetchRequest.predicate = predicate
    }

    fetchRequest.returnsObjectsAsFaults = false
  var items = NSArray()
   do { items = try managedObjectContext .executeFetchRequest(fetchRequest)
   } catch {
       print("Fetch Request Failed")
   }
    return items}}

The error is coming in the code-

    fetchRequest.entity = entityDescription
     if (predicate != nil){
       fetchRequest.predicate = predicate!
   }

I am not understanding where am going wrong. Any help appreciated. Thanks in advance

Upvotes: 1

Views: 3278

Answers (1)

Alexander
Alexander

Reputation: 63137

In an if let statement, the new variable name is bound only for the duration of the if let scope. You can't use it afterwards. What you're after is the guard statement:

guard let entityDescription = NSEntityDescription.entityForName(className as String, inManagedObjectContext: managedObjectContext) else {
    //handle error here
    return
}

fetchRequest.entity = entityDescription
if let predicate = predicate {
    fetchRequest.predicate = predicate
}

Upvotes: 1

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