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Realm

Realm is a mobile database that runs directly inside phones, tablets or wearables. This repository holds the source code for the C++ SDK Preview.

Why Use Realm

  • Intuitive to Developers: Realm’s object-oriented data model is simple to learn, doesn’t need an ORM, and lets you write less code.
  • Designed for Offline Use: Realm’s local database persists data on-disk, so apps work as well offline as they do online.
  • Built for Mobile: Realm is fully-featured, lightweight, and efficiently uses memory, disk space, and battery life.

Object-Oriented: Streamline Your Code

Realm was built for mobile developers, with simplicity in mind. The idiomatic, object-oriented data model can save you thousands of lines of code.

#include <cpprealm/sdk.hpp> using namespace realm; // Define your models like regular structs. struct Dog { std::string name; int64_t age; }; REALM_SCHEMA(Dog, name, age) struct Person { primary_key<std::string> _id; std::string name; int64_t age; // Create relationships by pointing an Object field to another Class Dog* dog; }; REALM_SCHEMA(Person, _id, name, age, dog) // Use them like regular objects. auto dog = Dog { .name = "Rex", .age = 1 }; std::cout << "name of dog: " << dog.name << std::endl; auto person = Person(); person._id = "something unique"; person.name = "John"; person.dog = &dog; // Get the default Realm with automatic schema discovery. realm::db_config config; auto realm = db(std::move(config)); // Persist your data easily with a write transaction auto managed_person = realm.write([&realm, &person] { return realm.add(std::move(person)); }); // Query with type safety. auto dogs = realm.objects<Dog>(); auto adult_dogs = dogs.where([](auto& d) { return d.age > 2; });

Live Objects: Build Reactive Apps

Realm’s live objects mean data updated anywhere is automatically updated everywhere.

// Open the default realm. realm::db_config config; auto realm = db(std::move(config)); realm::notification_token token; auto dog = Dog { .name = "Max" }; // Create a dog in the realm. auto managed_dog = realm.write([&realm, &dog] { return realm.add(std::move(dog)); }); // Set up the listener & observe object notifications. token = managed_dog.observe([](auto&& change) { if (change.error) { std::cout<<"An error occurred: "<<error<<std::endl; } else if (change.is_deleted) { std::cout<<"The object was deleted."<<std::endl; } else { std::cout << "Property " << property.name << " changed to " << property.new_value << std::endl; } } // Update the dog's name to see the effect. realm.write([&managed_dog] { managed_dog.name = "Wolfie" });

Data Sync

The Atlas Device Sync makes it simple to keep data in sync across users, devices, and your backend in real-time.

auto app = realm::App("<app-id>"); auto user = app.login(realm::App::credentials::anonymous()).get(); auto realm = db(user.flexible_sync_configuration()); auto cars = realm.results<Car>(); realm.write([&cars](){ for (auto& car : cars) { car.accelerate(); } });

Getting Started

See the detailed instructions in our docs.

The cpprealm API reference docs can be generated locally using Doxygen.

Installing Realm

Prerequisites

To build the Realm C++ SDK, you need CMake 3.20 or newer and a standard set of build tools. This includes a C/C++ compiler and a build system like GNU make. Realm is thoroughly tested with both GCC and Clang. It is compatible with GCC 8.3 and newer, as well as with Clang 9 and newer. Your compiler must support C++17.

Ubuntu 18.04 or greater

sudo apt-get install build-essential sudo apt-get install libcurl4-openssl-dev sudo apt-get install libuv1-dev sudo apt-get install libprocps-dev sudo apt-get install libssl-dev sudo apt-get install zlib1g-dev sudo apt-get install cmake 
  • If you are using a GCC version <= 9 and encounter an SSL linking error add the -DREALM_USE_SYSTEM_OPENSSL=ON cmake option.

macOS

On macOS, Clang is used as the C/C++ compiler by default. Clang is installed as part of Xcode. Xcode 13.1 or newer is required, and can be installed via the Mac App Store.

Setting up a development environment can conveniently be achieved using a package manager called brew. See https://brew.sh for install instructions.

brew install cmake 

Windows

On Windows, navigate to the following websites in your browser to download the appropriate installers.

Building

git submodule update --init --recursive mkdir build.debug cd build.debug cmake -D CMAKE_BUILD_TYPE=debug .. sudo cmake --build . --target install

You can then link to your library with -lcpprealm.

Note: If your target is Windows make sure to add the MSVC_RUNTIME_LIBRARY property to your target like so:

set_property(TARGET My_Target PROPERTY MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>") # If building in release use `CONFIG:Release>:Release` 

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