Configurar y abrir un Realm - Flutter SDK

Abrir un reino solo local

Para crear un dominio que solo persista datos localmente, cree una configuración con Configuration.local(). Debe proporcionar una lista de esquemas como argumento.

Pasar el Configuration al constructor del reino.

final config = Configuration.local([Car.schema]);
final realm = Realm(config);

You can now use that realm instance to work with objects in the database.

Open a Synced Realm

To open a realm that synchronizes data with Atlas using Device Sync, refer to Open a Synced Realm.

Open an In-Memory Realm

To create a realm that runs in memory without being persisted, create your Configuration with Configuration.inMemory(). You must provide a list of schemas as an argument. In-memory realms cannot also be read-only.

Pass the Configuration to the Realm constructor.

final config = Configuration.inMemory([Car.schema]);
final realm = Realm(config);

Open a Read-Only Realm

Puedes abrir un dominio existente en modo de solo lectura. Para ello, añade readOnly: true a tu objeto Configuration.

Solo puedes abrir reinos existentes en modo de solo lectura. Si intentas escribir en un realm de solo lectura, se producirá un error.

final config = Configuration.local([Car.schema], isReadOnly: true);
final realm = Realm(config);

Establecer archivos FIFO especiales personalizados

Establece un valor para la ubicación de archivos especiales FIFO de Realm. Abrir un Realm crea una serie de archivos especiales FIFO livianos que coordinan el acceso al Realm a través de hilos y procesos. Si el archivo Realm está en una ubicación que no permite la creación de archivos especiales FIFO (como los sistemas de archivos FAT32), entonces el Realm no puede abrirse. En este caso, Realm necesita una ubicación diferente para almacenar estos archivos. Agrega fifoFilesFallbackPath: <Your Custom FIFO File Path> a tu objeto Configuration.

Esta propiedad se ignora si el directorio del archivo realm permite archivos especiales FIFO.

final config = Configuration.local([Car.schema],
    fifoFilesFallbackPath: "./fifo_folder");
final realm = Realm(config);

Add Initial Data to Realm

Use initialDataCallback() to invoke a callback function the first time that you open a realm. The function only executes the first time you open that realm on the device. The realm instance passed to the callback function already has a write transaction open, so you do not need to wrap write operations in a Realm.write() transaction block. initialDataCallback can be useful for adding initial data to your application the first time that it is opened on a device.

void dataCb(Realm realm) {
  realm.add(Car(ObjectId(), 'Honda'));
}
final config =
    Configuration.local([Car.schema], initialDataCallback: dataCb);
final realm = Realm(config);
Car honda = realm.all<Car>()[0];

Personalizar la configuración por defecto

You can customize the default path where Realm stores database files and the default name given to database files.

Use the static Configuration.defaultRealmName and Configuration.defaultRealmPath to set default configuration for all realms opened within an application.

Configuration.defaultRealmName = "myRealmName.realm";
final customDefaultRealmPath = path.join(
    (await Directory.systemTemp.createTemp()).path,
    Configuration.defaultRealmName);
Configuration.defaultRealmPath = customDefaultRealmPath;
// Configurations used in the application will use these values
final config = Configuration.local([Car.schema]);
// The path is your system's temp directory
// with the file named 'myRealmName.realm'
print(config.path);

You can also check where realm stores the files by default using the static getter Configuration.defaultStoragePath. The value for this property varies depending on the platform you are using the SDK on and whether you are using the Dart or Flutter versions of Realm. Check the value of Configuration.defaultStoragePath in your application to see where realm files are stored in your environment.

final storagePath = Configuration.defaultStoragePath;
// See value in your application
print(storagePath);

Manage Schema Changes

For more information about managing schema changes when configuring a realm, refer to the Update a Realm Object Schema documentation.

Encrypt a Realm

You can encrypt your local realm to ensure data security. For more information, see Encrypt a Realm.

Compactar un Realm

You can reduce the local realm file size to improve performance and manage file size in a resource-constrained environment. For more information, refer to Compact a Realm.