更新一个属性核心数据
答
尝试下面的例子可能是helpful.Replace您实体名称。
var appDel:AppDelegate = (UIApplication.sharedApplication().delegate as! AppDelegate)
var context: NSManagedObjectContext = appDel.managedObjectContext!
var request = NSFetchRequest(entityName: "Params")
var params = NSEntityDescription.insertNewObjectForEntityForName("Params", inManagedObjectContext: context) as! NSManagedObject
if let fetchResults = appDel.managedObjectContext!.executeFetchRequest(fetchRequest, error: nil) as? [NSManagedObject] {
if fetchResults.count != 0{
for (var v = 0 ; v < fetchResults.count ; v++) {
var managedObject = fetchResults[v]
println(fetchResults)
managedObject.setValue("-1", forKey: "value")
context.save(nil)
}
}
}
答
为SWIFT 3
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let managedContext = appDelegate.managedObjectContext
let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Params")
do{
if let fetchResults = try managedContext.fetch(request) as? [NSManagedObject] {
if fetchResults.count != 0 {
for index in 0...fetchResults.count-1 {
let managedObject = fetchResults[index]
managedObject.setValue("-1", forKey: "value")
}
try managedContext.save()
}
}
} catch let error as NSError {
print("Could not fetch \(error), \(error.userInfo)")
}