How to use Core Data with your Swift App

Core data is provided by the Apple to be used in their applications as a way to store data rather Objective-C or Swift. Core Data is faster than SQLite and a efficient way to manage the data in your app. No doubt that core data uses SQLite as a backing engine.

Core data has a very vast scope rather than just managing the database. That we will explore later but for now we will just focus on basic inserting and retrieving of data from your core data.

1. Create a new project with Swift as the language, and enabling the Core Data. My project name will be CoreData
   


2. You’ll see that Xcode has produced an additional file named CoreData.xcdatamodeld.
   


3. Open up this file and you will find the core data model editor.


4. After that add the entity and rename it to Transactions follow the marks on the image below
   


5. Now after that add the attributes in your entity "Transaction"
   


6. We have successfully created the “Transactions” entity. Now in the menu bar go to Editor->Create NSManagedObject Subclass. In the first prompt check on CoreData model click next and after that check on Transactions entity. You will see that a swift file will be created by your Xcode template names Transactions.swift .


7. When you open Transactions.swift file you will find the below written code.

   import Foundation
   import CoreData
   
   class Transacitons: NSManagedObject {
   
       @NSManaged var name: String
       @NSManaged var age: NSNumber
   }
           



8. Now after that instantiate instance of Transaction entity. Go to your view scontroller and in the viewDidLoadMethod() write this code.

   override func viewDidLoad() {
       super.viewDidLoad()
    
       let newItem = NSEntityDescription.insertNewObjectForEntityForName("Transactions", inManagedObjectContext: self.managedObjectContext!) as! LogItem
   
   newItem.name = "Manu Gupta"
   newItem.age = "23"
   }
           



9. Now we have added the newItem in our entity and set both it’s name and age attribute. Let get those values back from coreData.


10. Lets fetch our data in viewDidAppear method with the following code.

    	override func viewDidAppear(animated: Bool) {
        super.viewDidAppear(animated)
         
        // Create a new fetch request using the LogItem entity
        let fetchRequest = NSFetchRequest(entityName: "Transactions")
         
        // Execute the fetch request, and cast the results to an array of LogItem objects
        if let fetchResults = managedObjectContext!.executeFetchRequest(fetchRequest, error: nil) as? [Transactions] {
             
            // Create an Alert, and set it's message to whatever the itemText is
            let alert = UIAlertController(title: fetchResults[0].name,
                message: fetchResults[0].age,
                preferredStyle: .Alert)
             
            // Display the alert
            self.presentViewController(alert,
                animated: true,
                completion: nil)
        }
    }
            



11. In this blog you have created the core data, inserted and fetched back the records. This is the first step to use persistent storage in your application

         Thanks and feel free to contact @ [email protected]