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How to Build a CRUD App for iOS with Objective-C?

27min
Overview
In this walkthrough, you will discover how to create a simple CRUD (create, read, update, delete) application for iOS using Objective-C. 
We will utilize Back4app as the backend to manage your data, ensuring a smooth integration of a backend with your iOS app. This guide covers everything from setting up a Back4app project to implementing essential CRUD operations using the Parse iOS SDK.
Initially, you'll set up a Back4app project titled Basic-CRUD-App-iOS. This project will serve as your data repository and allow you to design a flexible data model with classes such as Items and Users. You can define these classes manually in the Back4app dashboard or leverage the integrated AI Agent to streamline the process.
After configuring your backend, you will integrate it with your Objective-C iOS application. The tutorial includes code examples to initialize the Parse SDK, perform CRUD operations, and implement secure user authentication.
By the end of this tutorial, you will have built a production-ready iOS application that performs fundamental CRUD functions along with secure user management.
Key Concepts
Learn how to develop an iOS CRUD app using Objective-C with a robust backend.
Understand how to design and integrate a scalable backend using Back4app.
Utilize Back4app’s Admin App for efficient data management.
Implement secure data handling with ACLs and user authentication using the Parse iOS SDK.
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Prerequisites
Before you begin, ensure you have:
A Back4app account with an active project.
Need help? Refer to Getting Started with Back4app.
Xcode installed with a configured iOS development environment.
This tutorial assumes familiarity with Objective-C and iOS development.
Basic understanding of object-oriented programming and REST APIs.
Brush up on the Objective-C documentation if needed.
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Step 1 – Project Initialization
Creating Your Back4app Project
Log in to your Back4app account.
Click the “New App” button on your dashboard.
Name your project: Basic-CRUD-App-iOS and follow the on-screen prompts to complete the setup.
Create New Project
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Once created, your project appears on the dashboard, serving as the backbone for your app’s data management.
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Step 2 – Crafting the Data Model
Setting Up Your Data Structures
For this iOS CRUD app, you need to define key classes in your Back4app project. Below are the primary classes and their fields:
1. Items Class
This class stores details about each item.
Field
Data Type
Purpose
_id
ObjectId
Auto-generated unique identifier.
title
String
The item’s name.
description
String
A brief summary of the item.
createdAt
Date
Timestamp when the item was created.
updatedAt
Date
Timestamp for the last update.
2. Users Class
This class manages user credentials and authentication.
Field
Data Type
Purpose
_id
ObjectId
Automatically generated identifier.
username
String
Unique username for the user.
email
String
User’s unique email address.
passwordHash
String
Securely stored user password.
createdAt
Date
Account creation timestamp.
updatedAt
Date
Last modification timestamp.
You can set up these classes via the Back4app dashboard.
Create New Class
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You add fields by selecting the data type, naming the field, assigning default values, and marking mandatory fields.
Create Column
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Using the Back4app AI Agent for Schema Design
The integrated AI Agent can automatically build your data schema based on your description. This feature simplifies the setup process and ensures your data model meets the app requirements.
How to Use the AI Agent:
Access the AI Agent:
Open your Back4app dashboard and navigate to the AI Agent within your project settings.
Detail Your Data Model:
Enter a prompt describing the required classes and fields.
Review and Confirm:
Once the AI generates a schema proposal, review it and confirm to apply the changes.
Example Prompt
Text
Create the following classes in my Back4app project:

1) Class: Items
- Fields:
  - _id: ObjectId (auto-generated)
  - title: String
  - description: String
  - createdAt: Date (auto-generated)
  - updatedAt: Date (auto-updated)

2) Class: Users
- Fields:
  - _id: ObjectId (auto-generated)
  - username: String (unique)
  - email: String (unique)
  - passwordHash: String
  - createdAt: Date (auto-generated)
  - updatedAt: Date (auto-updated)
Create the following classes in my Back4app project:

1) Class: Items
- Fields:
  - _id: ObjectId (auto-generated)
  - title: String
  - description: String
  - createdAt: Date (auto-generated)
  - updatedAt: Date (auto-updated)

2) Class: Users
- Fields:
  - _id: ObjectId (auto-generated)
  - username: String (unique)
  - email: String (unique)
  - passwordHash: String
  - createdAt: Date (auto-generated)
  - updatedAt: Date (auto-updated)
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This method saves time and ensures consistency in your data structure.
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Step 3 – Enabling the Admin App & Managing Data
Overview of the Admin App
Back4app's Admin App provides a user-friendly, no-code interface for managing your backend data. Its drag-and-drop features allow you to easily create, view, modify, and delete records.
Activating the Admin App
Go to the “More” menu in your Back4app dashboard.
Select “Admin App” and click “Enable Admin App.”
Establish your admin account by setting up initial credentials, which also configures system roles like B4aAdminUser.
Enable Admin App
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After activation, log in to the Admin App to manage your data efficiently.
Admin App Dashboard
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Managing CRUD Operations via the Admin App
Within the Admin App, you can:
Add Records: Click “Add Record” within a class (e.g., Items) to insert new data.
Edit Records: Select any record to view or update its fields.
Delete Records: Remove entries that are no longer required.
This streamlined interface significantly simplifies data management tasks.
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Step 4 – Connecting Your iOS Application with Back4app
With the backend set up, the next step is integrating your iOS app with Back4app using the Parse iOS SDK.
Option A: Utilizing the Parse iOS SDK in Objective-C
Include the Parse SDK:
Add the Parse framework to your Xcode project. You can use CocoaPods by adding the following to your Podfile:
Ruby
pod 'Parse'
pod 'Parse'
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Initialize Parse in Your AppDelegate:
Open your AppDelegate.m and add the initialization code in the application:didFinishLaunchingWithOptions: method:
ObjectiveC
// AppDelegate.m
#import <Parse/Parse.h>

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    [Parse initializeWithConfiguration:[ParseClientConfiguration configurationWithBlock:^(id<ParseMutableClientConfiguration> configuration) {
        configuration.applicationId = @"YOUR_APPLICATION_ID";
        configuration.clientKey = @"YOUR_IOS_KEY";
        configuration.server = @"https://parseapi.back4app.com";
    }]];
    return YES;
}
// AppDelegate.m
#import <Parse/Parse.h>

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    [Parse initializeWithConfiguration:[ParseClientConfiguration configurationWithBlock:^(id<ParseMutableClientConfiguration> configuration) {
        configuration.applicationId = @"YOUR_APPLICATION_ID";
        configuration.clientKey = @"YOUR_IOS_KEY";
        configuration.server = @"https://parseapi.back4app.com";
    }]];
    return YES;
}
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Implement CRUD Methods in Objective-C:
Create a service class, e.g., ItemsService.m, to handle CRUD operations:
ObjectiveC
// ItemsService.m
#import "ItemsService.h"
#import <Parse/Parse.h>

@implementation ItemsService

- (void)createItemWithTitle:(NSString *)title description:(NSString *)description {
    PFObject *item = [PFObject objectWithClassName:@"Items"];
    item[@"title"] = title;
    item[@"description"] = description;
    [item saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
        if (succeeded) {
            NSLog(@"Item created successfully.");
        } else {
            NSLog(@"Error creating item: %@", error.localizedDescription);
        }
    }];
}

- (void)fetchItemsWithCompletion:(void (^)(NSArray *items, NSError *error))completion {
    PFQuery *query = [PFQuery queryWithClassName:@"Items"];
    [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
        completion(objects, error);
    }];
}

- (void)updateItemWithObjectId:(NSString *)objectId newTitle:(NSString *)newTitle newDescription:(NSString *)newDescription {
    PFQuery *query = [PFQuery queryWithClassName:@"Items"];
    [query getObjectInBackgroundWithId:objectId block:^(PFObject *item, NSError *error) {
        if (item) {
            item[@"title"] = newTitle;
            item[@"description"] = newDescription;
            [item saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
                if (succeeded) {
                    NSLog(@"Item updated successfully.");
                } else {
                    NSLog(@"Error updating item: %@", error.localizedDescription);
                }
            }];
        } else {
            NSLog(@"Error fetching item: %@", error.localizedDescription);
        }
    }];
}

- (void)deleteItemWithObjectId:(NSString *)objectId {
    PFQuery *query = [PFQuery queryWithClassName:@"Items"];
    [query getObjectInBackgroundWithId:objectId block:^(PFObject *item, NSError *error) {
        if (item) {
            [item deleteInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
                if (succeeded) {
                    NSLog(@"Item deleted successfully.");
                } else {
                    NSLog(@"Error deleting item: %@", error.localizedDescription);
                }
            }];
        } else {
            NSLog(@"Error fetching item: %@", error.localizedDescription);
        }
    }];
}

@end
// ItemsService.m
#import "ItemsService.h"
#import <Parse/Parse.h>

@implementation ItemsService

- (void)createItemWithTitle:(NSString *)title description:(NSString *)description {
    PFObject *item = [PFObject objectWithClassName:@"Items"];
    item[@"title"] = title;
    item[@"description"] = description;
    [item saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
        if (succeeded) {
            NSLog(@"Item created successfully.");
        } else {
            NSLog(@"Error creating item: %@", error.localizedDescription);
        }
    }];
}

- (void)fetchItemsWithCompletion:(void (^)(NSArray *items, NSError *error))completion {
    PFQuery *query = [PFQuery queryWithClassName:@"Items"];
    [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
        completion(objects, error);
    }];
}

- (void)updateItemWithObjectId:(NSString *)objectId newTitle:(NSString *)newTitle newDescription:(NSString *)newDescription {
    PFQuery *query = [PFQuery queryWithClassName:@"Items"];
    [query getObjectInBackgroundWithId:objectId block:^(PFObject *item, NSError *error) {
        if (item) {
            item[@"title"] = newTitle;
            item[@"description"] = newDescription;
            [item saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
                if (succeeded) {
                    NSLog(@"Item updated successfully.");
                } else {
                    NSLog(@"Error updating item: %@", error.localizedDescription);
                }
            }];
        } else {
            NSLog(@"Error fetching item: %@", error.localizedDescription);
        }
    }];
}

- (void)deleteItemWithObjectId:(NSString *)objectId {
    PFQuery *query = [PFQuery queryWithClassName:@"Items"];
    [query getObjectInBackgroundWithId:objectId block:^(PFObject *item, NSError *error) {
        if (item) {
            [item deleteInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
                if (succeeded) {
                    NSLog(@"Item deleted successfully.");
                } else {
                    NSLog(@"Error deleting item: %@", error.localizedDescription);
                }
            }];
        } else {
            NSLog(@"Error fetching item: %@", error.localizedDescription);
        }
    }];
}

@end
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Option B: Employing REST or GraphQL
If you prefer not to use the Parse SDK, you can interact with Back4app through RESTful API calls. For instance, to retrieve items via REST:
ObjectiveC
#import <Foundation/Foundation.h>

@interface RestClient : NSObject
+ (void)fetchItems;
@end

@implementation RestClient
+ (void)fetchItems {
    NSURL *url = [NSURL URLWithString:@"https://parseapi.back4app.com/classes/Items"];
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
    [request setHTTPMethod:@"GET"];
    [request setValue:@"YOUR_APPLICATION_ID" forHTTPHeaderField:@"X-Parse-Application-Id"];
    [request setValue:@"YOUR_REST_API_KEY" forHTTPHeaderField:@"X-Parse-REST-API-Key"];

    NSURLSessionDataTask *dataTask = [[NSURLSession sharedSession] dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
        if (error) {
            NSLog(@"Error fetching items: %@", error.localizedDescription);
        } else {
            NSString *result = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
            NSLog(@"Response: %@", result);
        }
    }];
    [dataTask resume];
}
@end
#import <Foundation/Foundation.h>

@interface RestClient : NSObject
+ (void)fetchItems;
@end

@implementation RestClient
+ (void)fetchItems {
    NSURL *url = [NSURL URLWithString:@"https://parseapi.back4app.com/classes/Items"];
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
    [request setHTTPMethod:@"GET"];
    [request setValue:@"YOUR_APPLICATION_ID" forHTTPHeaderField:@"X-Parse-Application-Id"];
    [request setValue:@"YOUR_REST_API_KEY" forHTTPHeaderField:@"X-Parse-REST-API-Key"];

    NSURLSessionDataTask *dataTask = [[NSURLSession sharedSession] dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
        if (error) {
            NSLog(@"Error fetching items: %@", error.localizedDescription);
        } else {
            NSString *result = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
            NSLog(@"Response: %@", result);
        }
    }];
    [dataTask resume];
}
@end
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Choose the approach that best suits your project's needs.
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Step 5 – Securing Your Backend
Configuring Access Control Lists (ACLs)
To safeguard your data, configure ACLs for your objects. For instance, to create an item visible only to its owner:
ObjectiveC
#import <Parse/Parse.h>

- (void)createPrivateItemWithTitle:(NSString *)title description:(NSString *)description owner:(PFUser *)owner {
    PFObject *item = [PFObject objectWithClassName:@"Items"];
    item[@"title"] = title;
    item[@"description"] = description;

    PFACL *acl = [PFACL ACLWithUser:owner];
    [acl setPublicReadAccess:NO];
    [acl setPublicWriteAccess:NO];
    item.ACL = acl;

    [item saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
        if (succeeded) {
            NSLog(@"Private item created.");
        } else {
            NSLog(@"Error saving item: %@", error.localizedDescription);
        }
    }];
}
#import <Parse/Parse.h>

- (void)createPrivateItemWithTitle:(NSString *)title description:(NSString *)description owner:(PFUser *)owner {
    PFObject *item = [PFObject objectWithClassName:@"Items"];
    item[@"title"] = title;
    item[@"description"] = description;

    PFACL *acl = [PFACL ACLWithUser:owner];
    [acl setPublicReadAccess:NO];
    [acl setPublicWriteAccess:NO];
    item.ACL = acl;

    [item saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
        if (succeeded) {
            NSLog(@"Private item created.");
        } else {
            NSLog(@"Error saving item: %@", error.localizedDescription);
        }
    }];
}
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Setting Class-Level Permissions (CLPs)
Use the Back4app dashboard to adjust CLPs, ensuring that only authenticated users can access certain classes by default.
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Step 6 – Implementing User Authentication
Managing User Accounts
Back4app leverages Parse’s native User class for managing user authentication. In your iOS application, you can implement registration and login as follows:
ObjectiveC
#import <Parse/Parse.h>

@interface AuthService : NSObject
+ (void)signUpWithUsername:(NSString *)username password:(NSString *)password email:(NSString *)email;
+ (void)logInWithUsername:(NSString *)username password:(NSString *)password;
@end

@implementation AuthService
+ (void)signUpWithUsername:(NSString *)username password:(NSString *)password email:(NSString *)email {
    PFUser *user = [PFUser user];
    user.username = username;
    user.password = password;
    user.email = email;

    [user signUpInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
        if (succeeded) {
            NSLog(@"User successfully registered!");
        } else {
            NSLog(@"Sign up error: %@", error.localizedDescription);
        }
    }];
}

+ (void)logInWithUsername:(NSString *)username password:(NSString *)password {
    [PFUser logInWithUsernameInBackground:username password:password block:^(PFUser *user, NSError *error) {
        if (user) {
            NSLog(@"User logged in: %@", user.username);
        } else {
            NSLog(@"Login failed: %@", error.localizedDescription);
        }
    }];
}
@end
#import <Parse/Parse.h>

@interface AuthService : NSObject
+ (void)signUpWithUsername:(NSString *)username password:(NSString *)password email:(NSString *)email;
+ (void)logInWithUsername:(NSString *)username password:(NSString *)password;
@end

@implementation AuthService
+ (void)signUpWithUsername:(NSString *)username password:(NSString *)password email:(NSString *)email {
    PFUser *user = [PFUser user];
    user.username = username;
    user.password = password;
    user.email = email;

    [user signUpInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
        if (succeeded) {
            NSLog(@"User successfully registered!");
        } else {
            NSLog(@"Sign up error: %@", error.localizedDescription);
        }
    }];
}

+ (void)logInWithUsername:(NSString *)username password:(NSString *)password {
    [PFUser logInWithUsernameInBackground:username password:password block:^(PFUser *user, NSError *error) {
        if (user) {
            NSLog(@"User logged in: %@", user.username);
        } else {
            NSLog(@"Login failed: %@", error.localizedDescription);
        }
    }];
}
@end
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This approach also extends to session management, password resets, and additional authentication features.
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Step 7 – Conclusion and Future Directions
Congratulations! You have successfully built an iOS CRUD application using Objective-C, fully integrated with Back4app. 
Throughout this guide, you set up a project named Basic-CRUD-App-iOS, designed core classes for Items and Users, and managed your backend using the Admin App. 
Additionally, you connected your app using the Parse iOS SDK, implemented CRUD operations, and secured your data with ACLs.
Next Steps:
Expand the Application:
Incorporate additional features like advanced search, detailed item views, or real-time updates.
Enhance Backend Capabilities:
Explore cloud functions, integrate third-party APIs, or refine role-based access control.
Deepen Your Expertise:
Visit the Back4app documentation for further insights and tutorials.
Happy coding and best of luck with your iOS CRUD project!
Field	Data Type	Purpose
_id	ObjectId	Auto-generated unique identifier.
title	String	The item’s name.
description	String	A brief summary of the item.
createdAt	Date	Timestamp when the item was created.
updatedAt	Date	Timestamp for the last update.
Field	Data Type	Purpose
_id	ObjectId	Automatically generated identifier.
username	String	Unique username for the user.
email	String	User’s unique email address.
passwordHash	String	Securely stored user password.
createdAt	Date	Account creation timestamp.
updatedAt	Date	Last modification timestamp.
Updated 19 Feb 2025
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