/ /

/ /

SDK de Dispositivo Atlas

React Native SDK

CRUD

CRUD - Update - React Native SDK

Los SDK de dispositivos Atlas están obsoletos. Consulte deprecation page for details.

The examples on this page use the following schema:

class Task extends Realm.Object {
  static schema = {
    name: 'Task',
    properties: {
      _id: 'int',
      name: 'string',
      priority: 'int?',
      progressMinutes: 'int?',
      assignee: 'Person?',
    },
    primaryKey: '_id',
  };
}

class Task extends Realm.Object<Task> {
  _id!: number;
  name!: string;
  priority?: number;
  progressMinutes?: number;
  assignee?: Person;
  age?: number;
  static schema: ObjectSchema = {
    name: 'Task',
    properties: {
      _id: 'int',
      name: 'string',
      priority: 'int?',
      progressMinutes: 'int',
      assignee: 'Person?',
    },
    primaryKey: '_id',
  };
}

Actualizar un objeto

Puede agregar, modificar o eliminar propiedades de un objeto Realm de la misma manera que actualizaría cualquier otro objeto JavaScript. Pero debes hacerlo dentro de una transacción de escritura.

En el siguiente ejemplo de un TaskItem componente, nosotros:

Get access to the opened realm instance by calling the useRealm() hook within the component.
Retrieve a task by calling useObject() with "Task" and the _id parameter of the component.
Create a component method incrementTaskProgress() that performs a write transaction and increments the task's progressMinutes.
Renderizar el name y el progressMinutes de la tarea en la Interfaz de Usuario.
Añadir un onPressevento en el botón "incrementar" que llama incrementTaskProgress() a.

const TaskItem = ({_id}) => {
  const realm = useRealm();
  const myTask = useObject(Task, _id);
  const incrementTaskProgress = () => {
    if (myTask) {
      realm.write(() => {
        myTask.progressMinutes += 1;
      });
    }
  };
  if (myTask) {
    return (
      <>
        <Text>Task: {myTask.name}</Text>
        <Text>Progress made (in minutes):</Text>
        <Text>{myTask.progressMinutes}</Text>
        <Button
          onPress={() => incrementTaskProgress()}
          title='Increment Task Progress'
        />
      </>
    );
  } else {
    return <></>;
  }
};

const TaskItem = ({_id}: {_id: number}) => {
  const realm = useRealm();
  const myTask = useObject(Task, _id);
  const incrementTaskProgress = () => {
    if (myTask) {
      realm.write(() => {
        myTask.progressMinutes! += 1;
      });
    }
  };
  if (myTask) {
    return (
      <>
        <Text>Task: {myTask.name}</Text>
        <Text>Progress made (in minutes):</Text>
        <Text>{myTask.progressMinutes}</Text>
        <Button
          onPress={() => incrementTaskProgress()}
          title='Increment Task Progress'
        />
      </>
    );
  } else {
    return <></>;
  }
};

Tip

Actualizar objetos relacionados y incrustados

To update a property of an embedded object or a related object, modify the property with dot-notation or bracket-notation as if it were in a regular, nested object.

Upsert an Object

Para la inserción de un objeto dentro de una transacción de escritura, llama a Realm.create() con el modo de actualización establecido en modified. La operación inserta un nuevo objeto con la llave primaria proporcionada o actualiza un objeto existente que ya tiene esa llave primaria.

Nota

Upserting Requires Realm.create()

You must call Realm.create() within a write transaction to upsert an object. This is different than creating a new Realm Objects by calling the new operator.

En el siguiente ejemplo de un componente de CreateTaskItem:

Get access to the opened realm instance by calling the useRealm() hook within the component.
Perform a write transaction, and create a Task object with an _id value of 1234.
Call Realm.create() inside the write transaction to upsert a Task object by specifying the same _id and a different``progressMinutes`` and the update mode set to "modified".
Render the task's name and progressMinutes in the UI, showing the modified progress.

const CreateTaskItem = () => {
  const realm = useRealm();
  let myTask;
  realm.write(() => {
    // Add a new Task to the realm. Since no task with ID 1234
    // has been added yet, this adds the instance to the realm.
    myTask = realm.create(
      'Task',
      {_id: 1234, name: 'Wash the car', progressMinutes: 0},
      'modified',
    );
    // If an object exists, setting the third parameter (`updateMode`) to
    // "modified" only updates properties that have changed, resulting in
    // faster operations.
    myTask = realm.create(
      'Task',
      {_id: 1234, name: 'Wash the car', progressMinutes: 5},
      'modified',
    );
  });
  return (
    <>
      <Text>{myTask.name}</Text>
      <Text>Progress made (in minutes):</Text>
      <Text>{myTask.progressMinutes}</Text>
    </>
  );
};

const CreateTaskItem = () => {
  const realm = useRealm();
  const myTask: Realm.Object = realm.write(() => {
    // Add a new Task to the realm. Since no Task with ID 1234
    // has been added yet, this adds the instance to the realm.
    realm.create(
      'Task',
      {_id: 1234, name: 'Wash the car', progressMinutes: 0},
      'modified',
    );
    // If an object exists, setting the third parameter (`updateMode`) to
    // "modified" only updates properties that have changed, resulting in
    // faster operations.
    return realm.create(
      'Task',
      {_id: 1234, name: 'Wash the car', progressMinutes: 5},
      'modified',
    );
  });
  return (
    <>
      <Text>{myTask.name}</Text>
      <Text>Progress made (in minutes):</Text>
      <Text>{myTask.progressMinutes}</Text>
    </>
  );
};

Actualizar colección por lotes

To apply an update to a collection of objects, iterate through the collection (e.g. with for...of). In the loop, update each object individually.

In the following example of a TaskDashboard component, we:

Get access to the opened realm instance by calling the useRealm() hook within the component.
Recupera todas las tareas en la instancia Realm pasando Task al gancho useQuery().
Create a component method resetProgressOnAllTasks() that performs a write transaction. Within that write transaction, we bulk update all tasks by looping through them using for...of and set their progressMinutes to 0.
Map through the tasks to render a list of Text components displaying each task's name and progressMinutes.

const TaskDashboard = () => {
  const realm = useRealm();
  const tasks = useQuery(Task);
  const resetProgressOnAllTasks = () => {
    realm.write(() => {
      for (const task of tasks) {
        task.progressMinutes = 0;
      }
    });
  };
  return (
    <>
      {tasks.map(task => {
        <Text>
          {task.name} has {task.progressMinutes} minutes progressed
        </Text>;
      })}
      <Button
        onPress={resetProgressOnAllTasks}
        title='Reset Progress'
      />
    </>
  );
};

Volver

Lea

Borrar