CRUD - Delete - React Native SDK

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Delete an Object

Delete Multiple Objects
Delete All Objects in a Realm

Realm is now Atlas Device SDK – Learn More

The examples on this page use the following schema:

class Dog extends Realm.Object {
  static schema = {
    name: 'Dog',
    properties: {
      name: 'string',
      owners: {
        type: 'list',
        objectType: 'Person',
        optional: true,
      },
      age: 'int?',
    },
  };
}

class Dog extends Realm.Object<Dog> {
  name!: string;
  owner?: Realm.List<Person>;
  age?: number;
  static schema: ObjectSchema = {
    name: 'Dog',
    properties: {
      name: 'string',
      owners: {
        type: 'list',
        objectType: 'Person',
        optional: true,
      },
      age: 'int?',
    },
  };
}

Delete an Object

To delete an object from a realm, pass the object to Realm.delete() inside of a write transaction.

In the following example of a DogList component, we:

Get access to the opened realm instance by calling the useRealm() hook.
Retrieve all dogs in the realm instance by passing Dog to the useQuery() hook.
Create a component method deleteDog() that takes in a Dog object as a parameter. Within the method, we pass Realm.delete() the Dog object, deleting it from the realm.
Map through the dogs to render a list of Text components that contain a dog's name and a "Delete Dog" button.
Add an onPress event on the "Delete Dog" button that calls the component's deleteDog() method.

const DogList = () => {
  const realm = useRealm();
  const myDogs = useQuery(Dog);
  const deleteDog = deletableDog => {
    realm.write(() => {
      realm.delete(deletableDog);
    });
  };
  return (
    <>
      {myDogs.map(dog => {
        return (
          <>
            <Text>{dog.name}</Text>
            <Button
              onPress={() => deleteDog(dog)}
              title='Delete Dog'
            />
          </>
        );
      })}
    </>
  );
};

const DogList = () => {
  const realm = useRealm();
  const myDogs = useQuery(Dog);
  const deleteDog = (deletableDog: Dog) => {
    realm.write(() => {
      realm.delete(deletableDog);
    });
  };
  return (
    <>
      {myDogs.map(dog => {
        return (
          <>
            <Text>{dog.name}</Text>
            <Button
              onPress={() => deleteDog(dog)}
              title='Delete Dog'
            />
          </>
        );
      })}
    </>
  );
};

Important

Do not use objects after delete

You cannot access or modify an object after you have deleted it from a Realm. If you try to use a deleted object, Realm throws an error.

Delete Multiple Objects

You can delete multiple objects from a realm in a couple of ways:

To delete all objects of a given object type from a realm, pass the results of useQuery(<ObjectType>) to the Realm.delete() method inside of a write transaction.
To delete many specific objects from a realm, pass Collection.filtered() to Realm.delete() inside of a write transaction.

In the following example of a DogList component, we:

Retrieve the realm instance using the useRealm() hook.
Set a variable myDogs to all the Dog objects by passing the Dog class to the useQuery() hook.
Create a component method deleteAllYoungDogObjects() that performs a write transaction. Within the write transaction, we set a variable, youngDogs, to the result of myDogs.filtered() with a query to obtain all dogs younger than three. Then pass youngDogs to realm.delete(), deleting all young dogs from the realm.
Create a component method deleteAllDogObjects() that performs a write transaction. Within the write transaction, we pass myDogs to realm.delete(), deleting all the dogs from the realm.
Map through the dogs to render a list of Text components that contain a dog's name and age.
Add an onPress event on the "Delete Young Dog Objects" button that calls deleteAllYoungDogObjects(), deleting all young dogs from the realm, which triggers a re-render and removes them from the UI.
Add an onPress event on the "Delete All Dog Objects" button that calls deleteAllDogObjects(), deleting every dog from the realm, which triggers a re-render and removes them from the UI.

Note

When you delete objects from the realm instance, the component automatically re-renders and removes them from the UI.

const DogList = () => {
  const realm = useRealm();
  const myDogs = useQuery(Dog);
  const deleteAllYoungDogObjects = () => {
    const youngDogs = useQuery(Dog, dogs => {
      return dogs.filtered('age < 3');
    });
    realm.write(() => {
      realm.delete(youngDogs);
    });
  };
  const deleteAllDogObjects = () => {
    realm.write(() => {
      realm.delete(myDogs);
    });
  };
  return (
    <>
      {myDogs.map(dog => {
        return (
          <>
            <Text>{dog.name}</Text>
            <Text>{dog.age}</Text>
          </>
        );
      })}
      <Button
        onPress={() => deleteAllYoungDogObjects()}
        title='Delete Young Dog Objects'
      />
      <Button
        onPress={() => deleteAllDogObjects()}
        title='Delete All Dog Objects'
      />
    </>
  );
};

const DogList = () => {
  const realm = useRealm();
  const myDogs = useQuery(Dog);
  const deleteAllYoungDogObjects = () => {
    const youngDogs = useQuery(Dog, dogs => {
      return dogs.filtered('age < 3');
    });
    realm.write(() => {
      realm.delete(youngDogs);
    });
  };
  const deleteAllDogObjects = () => {
    realm.write(() => {
      realm.delete(myDogs);
    });
  };
  return (
    <>
      {myDogs.map(dog => {
        return (
          <>
            <Text>{dog.name}</Text>
            <Text>{dog.age}</Text>
          </>
        );
      })}
      <Button
        onPress={() => deleteAllYoungDogObjects()}
        title='Delete Young Dog Objects'
      />
      <Button
        onPress={() => deleteAllDogObjects()}
        title='Delete All Dog Objects'
      />
    </>
  );
};

Delete All Objects in a Realm

To delete all objects from the realm, call Realm.deleteAll() inside of a write transaction. This clears the realm of all object instances but does not affect the realm's schema.

In the following example of a DeleteProfileSettingsScreen component, we:

Get access to the opened realm instance by calling the useRealm() hook within the component.
Create a component method deleteAllData() that performs a write transaction and calls Realm.deleteAll(), deleting all objects from the realm.
Add an onPress event on the "Delete all data" button that calls deleteAllData().

const DeleteProfileSettingsScreen = () => {
  const realm = useRealm();
  const deleteAllData = () => {
    realm.write(() => {
      realm.deleteAll();
    });
  };
  return (
    <>
      <Text>Delete all data in your profile:</Text>
      <Button
        onPress={deleteAllData}
        title='Delete all data'
      />
    </>
  );
};

const DeleteProfileSettingsScreen = () => {
  const realm = useRealm();
  const deleteAllData = () => {
    realm.write(() => {
      realm.deleteAll();
    });
  };
  return (
    <>
      <Text>Delete all data in your profile:</Text>
      <Button
        onPress={deleteAllData}
        title='Delete all data'
      />
    </>
  );
};

Tip

Delete All In Development

Realm.deleteAll() is a useful method to quickly clear out your realm in the course of development. For example, rather than writing a migration to update objects to a new schema, it may be faster to delete and then re-generate the objects with the app itself.

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