Ecosyste.ms: Awesome

An open API service indexing awesome lists of open source software.

Awesome Lists | Featured Topics | Projects

https://github.com/realm/realm-cpp

Realm C++
https://github.com/realm/realm-cpp

Last synced: 23 days ago
JSON representation

Realm C++

Awesome Lists containing this project

README

        

![Realm](./logo.png)

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.
* **[Device Sync](https://www.mongodb.com/docs/atlas/app-services/sync/)**: Makes it simple to keep data in sync across users, devices, and your backend in real-time. [Get started for free](https://www.mongodb.com/docs/realm/sdk/cpp/sync/) and [create the cloud backend](http://mongodb.com/realm/register?utm_medium=github_atlas_CTA&utm_source=realm_cpp_github).

## 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.

```cpp
#include

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 _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();
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.
```cpp
// 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: "<");
auto user = app.login(realm::App::credentials::anonymous()).get();
auto realm = db(user.flexible_sync_configuration());

auto cars = realm.results();
realm.write([&cars](){
for (auto& car : cars) {
car.accelerate();
}
});
```

## Getting Started

See the detailed instructions in our [docs](https://www.mongodb.com/docs/atlas/device-sdks/sdk/cpp/).

The API reference is located [here](https://www.mongodb.com/docs/realm-sdks/cpp/latest/).

## 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.

- Visual Studio 2019: https://www.visualstudio.com/
- CMake: https://cmake.org/download/

### Building

```sh
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$<$:Debug>") # If building in release use `CONFIG:Release>:Release`
```