CRUD Operation with Realm

Khushboo Gupta

20 January 2021

Hi guys, today we will learn about how to implement CRUD Operation with realm() in an iOS application.

Before starting to code first we need to know what a Realm() is

Realm() is a cross-platform mobile object database. It’s very fast, performance, and easy to use as compared to core data and SQLite. It is written in cross-platform C++, so it works exactly the same way on Android, iOS, macOS, or any other platform.

Realm()

Most of the Realm() is open-source, but the secret sauce behind Realm() Platform is the core DB engine written from scratch in C++.

code of CRUD Operation-

Create – In it, we can create a realm() Data.

For example-

 let realm = try! Realm()
              try! realm.write {
// your code
}

let realm = try! Realm()

try! realm.write {

// your code

}

Read – In it, we can read a realm() Data.

For example-

 let realm = try! Realm()
        guard let info = realm.objects(Info.self).first else {return}

1 2	let realm = try! Realm() guard let info = realm.objects(Info.self).first else {return}

Update – In it, we can Update a realm() Data.

For example-

try! realm.write {
    realm.add(name of change field, update: .modified)
}

try! realm.write {

realm.add(name of change field, update: .modified)

}

Delete – In it, we can Delete a realm() Data.

For example-

  try! realm.write {
                realm.deleteAll()
                
            }

try! realm.write {

realm.deleteAll()

}

Step of CRUD Operation –

install cocoa pods in Xcode
install realm pod file in Xcode
realm pod – pod ‘RealmSwift’
start working on code

Example of CRUD Operation –

we have taken an example where we know how to create, save, and update data in the realm().

step 1:-

create realmModel.swift file

import Foundation
import UIKit
import RealmSwift

class PersonDetail: Object{
    @objc dynamic var name  = ""
    @objc dynamic var age = ""
    @objc dynamic var dateOfBirth = ""
    
    convenience init(name: String, age: String, dateOfBirth:String) {
        self.init()
        self.name = name
        self.age = age
    self.dateOfBirth = dateOfBirth
        
    }
    
}

import Foundation

import UIKit

import RealmSwift

class PersonDetail: Object{

@objc dynamic var name = ""

@objc dynamic var age = ""

@objc dynamic var dateOfBirth = ""

convenience init(name: String, age: String, dateOfBirth:String) {

self.init()

self.name = name

self.age = age

self.dateOfBirth = dateOfBirth

}

step 2:

Create a view controller

step 3:

Create Table view Cell

import UIKit

class RealmTVTableViewCell: UITableViewCell {
   
    @IBOutlet weak var nameLabel: UILabel!
       
       @IBOutlet weak var dateOfBirthLabel: UILabel!
       @IBOutlet weak var ageLabel: UILabel!
    override func awakeFromNib() {
        super.awakeFromNib()
        // Initialization code
    } 
    override func setSelected(_ selected: Bool, animates: Bool){
      super.setSelected(selected, animated: animated)
      // Configuration the view for the selected state
    }

}

import UIKit

class RealmTVTableViewCell: UITableViewCell {

@IBOutlet weak var nameLabel: UILabel!

@IBOutlet weak var dateOfBirthLabel: UILabel!

@IBOutlet weak var ageLabel: UILabel!

override func awakeFromNib() {

super.awakeFromNib()

// Initialization code

}

override func setSelected(_ selected: Bool, animates: Bool){

super.setSelected(selected, animated: animated)

// Configuration the view for the selected state

}

step 4

Create view Controller

import UIKit
import RealmSwift

class ViewController: UIViewController {
    
    @IBOutlet weak var tableViewOutlet: UITableView!
    var buttonAlertBar = ButtonAlert()
    let items = try! Realm().objects(PersonDetail.self)
        let realm = try! Realm()
    override func viewDidLoad() {
        // create realm data
        if realm.isEmpty {
        try! realm.write {
            realm.deleteAll()
        }
        }

    }
   
    @IBAction func clickBarButton(_ sender: Any) {
        buttonAlertBar.alertAction(controller: self, value: 0, nameString: "" )
        buttonAlertBar.onEdit = { [weak self] (tableReload: Bool) in
            self!.tableViewOutlet.reloadData()
        }
    }
}


extension ViewController: UITableViewDataSource,UITableViewDelegate{



        func tableView(_tableView: UITableView, numberofRowInSection section: Int)-> {
        return items.count
        }

       func tableView(_tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let myCell = tableViewOutlet.dequeueReusableCell(withIdentifier: "RealmTVTableViewCell") as! RealmTVTableViewCell
        myCell.nameLabel.text = "Name :" + items[indexPath.row].name
        myCell.ageLabel.text = "Age :" + items[indexPath.row].age
        myCell.dateOfBirthLabel.text = "DOB :" + items[indexPath.row].dateOfBirth
        
        
        return myCell
    }

    func tableView(_tableView: UITableView, heightForRowAt indexPath: IndexPath) -? CGFloat {
        return 120
    }

     func tableView(_tableView: UITableView, commit edityingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
         // delete data in realm
          if editingStyle == .delete {
            try! realm.write {
                realm.delete(items[indexPath.row])
                
            }
           self.tableViewOutlet.deleteRows(at: [indexPath], with: .left)

            
          }
      }
}

import UIKit

import RealmSwift

class ViewController: UIViewController {

@IBOutlet weak var tableViewOutlet: UITableView!

var buttonAlertBar = ButtonAlert()

let items = try! Realm().objects(PersonDetail.self)

let realm = try! Realm()

override func viewDidLoad() {

// create realm data

if realm.isEmpty {

try! realm.write {

realm.deleteAll()

}

@IBAction func clickBarButton(_ sender: Any) {

buttonAlertBar.alertAction(controller: self, value: 0, nameString: "" )

buttonAlertBar.onEdit = { [weak self] (tableReload: Bool) in

self!.tableViewOutlet.reloadData()

}

extension ViewController: UITableViewDataSource,UITableViewDelegate{

func tableView(_tableView: UITableView, numberofRowInSection section: Int)-> {

return items.count

}

func tableView(_tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

let myCell = tableViewOutlet.dequeueReusableCell(withIdentifier: "RealmTVTableViewCell") as! RealmTVTableViewCell

myCell.nameLabel.text = "Name :" + items[indexPath.row].name

myCell.ageLabel.text = "Age :" + items[indexPath.row].age

myCell.dateOfBirthLabel.text = "DOB :" + items[indexPath.row].dateOfBirth

return myCell

}

func tableView(_tableView: UITableView, heightForRowAt indexPath: IndexPath) -? CGFloat {

return 120

}

func tableView(_tableView: UITableView, commit edityingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {

// delete data in realm

if editingStyle == .delete {

try! realm.write {

realm.delete(items[indexPath.row])

}

self.tableViewOutlet.deleteRows(at: [indexPath], with: .left)

}

It looks like this

. .

Conclusion

In this blog, we have discussed how to save, update, and delete the data in the database by using the CRUD Operation with Realm().

I hope this blog will help you in getting some basic knowledge about the CRUD Operation with Realm().

Thanks for reading!