CODEWITHSUNDEEP
swiftcore-datafetchlimit
Sae
Sae

Reputation: 77

Sort in CoreData

How can I use Sort in CoreData? I want to sort them by property, which is time

I also want to use these two threads. Someone knows how to use these two :

fetchOffset <==========

fetchLimit <===========

final class PersistantManager {
    private init(){}
    static let shared = PersistantManager()
    // MARK: - Core Data stack

     lazy var persistentContainer: NSPersistentContainer = {
         
         let container = NSPersistentContainer(name: "_chans_")
         container.loadPersistentStores(completionHandler: { (storeDescription, error) in
             if let error = error as NSError? {
                 
                 fatalError("Unresolved error \(error), \(error.userInfo)")
             }
         })
         return container
     }()

    lazy var context = persistentContainer.viewContext
     // MARK: - Core Data Saving support

     func save () {
         let context = persistentContainer.viewContext
         if context.hasChanges {
             do {
                 try context.save()
                print("success save")
             } catch {
                
                 let nserror = error as NSError
                 fatalError("Unresolved error \(nserror), \(nserror.userInfo)")
             }
         }
     }
    func fetch<T: NSManagedObject>(_ objectType : T.Type) -> [T] {
        let entityname = String(describing: objectType)
        let fetchrequest = NSFetchRequest<NSFetchRequestResult>(entityName: entityname)
        do {
            let fetchedobject = try context.fetch(fetchrequest) as? [T]
            return fetchedobject ?? [T]()
        }catch{
            print(error)
            return [T]()
        }
        
    }
}

and my code for fetch :

guard let Bookmarks = try! PersistantManager.shared.context.fetch(HistoryBookmarks_Coredata.fetchRequest()) as? [HistoryBookmarks_Coredata] else {return}

Upvotes: 0

Views: 131

Answers (1)

nighttalker
nighttalker

Reputation: 946

All you need to do is set the sort descriptors of the fetch request.

// replace "key" with the property you want to sort by
let sort = NSSortDescriptor(key: "key", ascending: false)
let fetchrequest = NSFetchRequest<NSFetchRequestResult>(entityName: entityname)
fetchrequest.sortDescriptors = [sort]

The fetchLimit specifies the maximum number of records to fetch.

The fetchOffset allows you to skip a specified number of rows.

If you want to know what a property is for, the documentation is a good place to start.

Upvotes: 1

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