Realm Swift Database - Deployment and Usage Guide

Prerequisites

macOS (for development) with Xcode 13.0 or later
iOS 11.0+, macOS 10.13+, tvOS 11.0+, or watchOS 4.0+ (for deployment)
Swift 5.0 or later
Optional: MongoDB Atlas Account for cloud sync features

Installation

Option 1: Swift Package Manager (Recommended)

In Xcode, go to File > Add Packages...
Enter the package URL: https://github.com/realm/realm-swift
Select the version or branch you want to use
Click Add Package

Option 2: CocoaPods

Add to your Podfile:
```
pod 'RealmSwift'
```
Run pod install

Option 3: Carthage

Add to your Cartfile:
```
github "realm/realm-swift"
```
Run carthage update
Drag the built framework into your Xcode project

Option 4: Manual Installation

Download the latest release from GitHub
Extract the XCFramework
Add the framework to your Xcode project

Configuration

Local Database (No Sync)

No configuration is required for local-only usage. Realm works out of the box with default settings.

With MongoDB Atlas Device Sync

Create a MongoDB Atlas Account at mongodb.com/realm/register
Create a new application in Atlas App Services
Enable Device Sync for your application
Download the configuration file (realm-configuration.json)
Add the configuration file to your Xcode project
Initialize Realm with the configuration:

let app = App(id: "your-app-id")
let config = app.currentUser.configuration(partitionValue: "your-partition")
let realm = try! Realm(configuration: config)

Encryption (Optional)

For encrypted databases, generate a 64-byte encryption key:

var key = Data(count: 64)
_ = key.withUnsafeMutableBytes { (pointer: UnsafeMutableRawBufferPointer) in
    guard let baseAddress = pointer.baseAddress else {
        fatalError("Failed to obtain base address")
    }
    SecRandomCopyBytes(kSecRandomDefault, 64, baseAddress)
}

let config = Realm.Configuration(encryptionKey: key)
let realm = try Realm(configuration: config)

Build & Run

Development

Open your project in Xcode
Build (Cmd+B) to compile
Run (Cmd+R) to test on simulator or device

Testing

Realm includes comprehensive test suites. To run tests:

# Clone the repository
git clone https://github.com/realm/realm-swift.git
cd realm-swift

# Open the workspace
open RealmSwift.xcworkspace

# Select the desired test target
# Run tests using Cmd+U

Sample Usage

// Define your models
class Dog: Object {
    @Persisted var name: String
    @Persisted var age: Int
}

class Person: Object {
    @Persisted(primaryKey: true) var _id: String
    @Persisted var name: String
    @Persisted var age: Int
    @Persisted var dogs: List<Dog>
}

// Use the database
let realm = try! Realm()
let dog = Dog()
dog.name = "Rex"
dog.age = 1

try! realm.write {
    realm.add(dog)
}

Deployment

iOS App Store

Ensure your app meets App Store Review Guidelines
Archive your application (Product > Archive)
Upload to App Store Connect
Submit for review

Enterprise Distribution

Build for the appropriate device configuration
Sign with your enterprise certificate
Distribute via your enterprise distribution method (e.g., MDM, enterprise store)

macOS App Store

Archive your application
Upload to App Store Connect
Submit for review

Note on Sync Features

If using MongoDB Atlas Device Sync, ensure your backend is properly configured and that your app has network connectivity for sync operations.

Troubleshooting

Common Issues

1. "Realm file is already open" Error

Cause: Multiple Realm instances trying to access the same file simultaneously.

Solution: Use a singleton pattern for Realm instances or ensure proper thread confinement.

class RealmManager {
    static let shared = RealmManager()
    private init() {}
    
    lazy var realm: Realm = {
        return try! Realm()
    }()
}

2. Migration Issues

Cause: Schema changes between app versions without proper migration.

Solution: Implement migration blocks:

let config = Realm.Configuration(
    schemaVersion: 2,
    migrationBlock: { migration, oldSchemaVersion in
        if oldSchemaVersion < 2 {
            // Migration logic here
        }
    }
)
let realm = try! Realm(configuration: config)

3. Sync Connection Issues

Cause: Network connectivity problems or misconfigured sync settings.

Solution:

Check your MongoDB Atlas configuration
Verify network connectivity
Check partition key configuration
Review sync permissions in Atlas App Services

4. Performance Issues

Cause: Large datasets or inefficient queries.