Delete Objects and Property Values

To delete an object from the database, pass the object to the db.remove() function inside of a write transaction.

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

Delete an object from the database by calling Realm.delete() in a write transaction block.

To delete an object from the database, use either the dynamic or static versions of the deleteFromRealm() method of a RealmObject subclass.

The following example shows how to delete one object from its realm with deleteFromRealm().

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

To delete a single RealmObject object, query for the object type using a filter that returns the specific object that you want to delete.

In the following example, we query for a Frog object with a specific primary key, and then pass the returned object to mutableRealm.delete() to delete it from the database:

To delete an object from the database, use either the dynamic or static versions of the deleteFromRealm() method of a RealmObject subclass.

The following example shows how to delete one object from its realm with deleteFromRealm().

To delete an object from the database, pass the object to -[RLMRealm deleteObject:] inside of a write transaction.

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

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

You can delete multiple objects within a write transaction.

To delete multiple objects at the same time, pass an IQueryable<T> query for the objects you want to delete to Realm.RemoveRange<T>.

Delete multiple objects from the database by calling Realm.deleteMany() in a write transaction block.

To delete an object from the database, use the deleteAllFromRealm() method of the RealmResults instance that contains the objects you would like to delete. You can filter the RealmResults down to a subset of objects using the where() method.

The following example demonstrates how to delete a collection from the database with deleteAllFromRealm().

To delete a collection of objects from the database, pass the collection to Realm.delete() inside of a write transaction.

To delete multiple objects at the same time, pass the object type to query() and specify a query that returns all objects that you want to delete.

In the following example, we query for the first three Frog objects whose species is "bullfrog", and then pass the results to mutableRealm.delete() to delete them from the database:

To delete an object from the database, use the deleteAllFromRealm() method of the RealmResults instance that contains the objects you would like to delete. You can filter the RealmResults down to a subset of objects using the where() method.

The following example demonstrates how to delete a collection from the database with deleteAllFromRealm().

To delete a collection of objects from the database, pass the collection to -[Realm deleteObjects:] inside of a write transaction.

To delete a collection of objects from the database, pass the collection to Realm.delete(_:) inside of a write transaction.

To delete a collection of objects from the database, pass the collection to Realm.delete() inside of a write transaction.

C++ does not currently provide an API to delete all objects of a type.

To delete all objects of a type, call Realm.RemoveAll<T>.

Delete all objects of a type in the database with Realm.deleteAll() in a write transaction block.

The following example demonstrates how to delete all Turtle instances from the database with delete().

To delete all objects of a given object type from the database, pass Realm.objects(<ObjectType>) to the Realm.delete() method inside of a write transaction.

To delete all objects of a specific type from the database at the same time, pass the object type to query() and leave the query filter empty to return all objects of that type.

In the following example, we query for all Frog objects, and then pass the results to mutableRealm.delete() to delete them all from the database:

The following example demonstrates how to delete all Turtle instances from the database with delete().

To delete all objects of a given object type from the database, pass the result of +[YourSDKObjectClass allObjectsInRealm:] to -[Realm deleteObjects:] inside of a write transaction. Replace YourSDKObjectClass with your SDK object class name.

To delete all objects of a given object type from the database, query for objects of the type you want to delete, and pass the result to Realm.delete(_:) inside of a write transaction.

To delete all objects of a given object type from the database, pass Realm.objects(<ObjectType>) to the Realm.delete() method inside of a write transaction.

C++ does not currently provide a method to delete all objects in the database. You can manually iterate through the objects and delete them if you need to clear the database.

To delete all managed objects in the database, call Realm.RemoveAll.

Dart does not provide an API to delete all objects in the database. Instead, you can iterate through the object types that the database manages and delete all objects of each type.

For more information, refer to the Delete All Objects of a Type section on this page.

The following example demonstrates how to delete everything from the database with deleteAll().

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

To delete all objects from the database at the same time, call mutableRealm.deleteAll(). This deletes all objects of all types.

The following example demonstrates how to delete everything from the database with deleteAll().

To delete all objects from the database, call -[RLMRealm deleteAllObjects] inside of a write transaction. This clears the database of all object instances but does not affect the database's schema.

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

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

In the following example, we call Realm.RemoveRange<T> to remove Ali's dogs collection, which is a to-many list property containing one or more Dog objects. Then, we call Realm.Remove() to delete Ali's Person object itself.

The following example demonstrates how to perform a chaining delete by first deleting all of Ali's turtles, then deleting Ali.

In the following example, we query for a Frog object named "Kermit", then iterate through the object's favoritePonds property and delete each Pond object. Then, we delete the Frog object itself:

The following example demonstrates how to perform a chaining delete by first deleting all of Ali's turtles, then deleting Ali.

In the following example, we have a specific Person object - ali. We delete the objects in Ali's dogs collection, which is a to-many list property containing one or more Dog objects. Then, we delete the ali Person object itself.

In the following example, we delete the objects in the person.dogs collection, which is a to-many list property containing one or more Dog objects. Then, we delete the Person object itself.

In the following example, we have a Business object with a list of embedded EmbeddedAddress objects. We query for and delete the Business object, which automatically deletes all of its embedded EmbeddedAddress objects:

// Delete the parent object
realm.write {
    val businessToDelete = query<Business>("name == $0", "Big Frog Corp.").find().first()
    // Delete the parent object (deletes all embedded objects)
    delete(businessToDelete)
}

In the following example, we have Contact objects with embedded EmbeddedAddress objects. We delete an EmbeddedAddress object directly and delete another through the parent object:

In this example, a Person has a to-one relationship to a Dog, and the Dog has an inverse relationship to Person. Setting the Person.dog relationship to nullptr removes the inverse relationship from the Dog object.

To delete the value of a mixed property, set its value to Null.

To delete the value of a mixed property, call RealmValue.nullValue().

To delete the value of a Mixed property, set it to null.

In the following example, we have a Frog object with a list of RealmAny properties, and we clear the first RealmAny property value:

To delete the value of an RLMValue, set it to nil.

To delete the value of an AnyRealmValue, set it to .none.

To delete the value of a Mixed property, set it to null.

You can delete a list element with erase(), or remove all elements from the list with clear().

You can remove one or more elements from a list within a write transaction.

Deleting an object from the database will remove it from any lists where it existed. Therefore, a list of objects will never contain deleted objects. However, lists of primitive types can contain null values. If you do not want to allow null values in a list, then either use non-nullable types in the list declaration (for example, use IList<double> instead of IList<double?>). If you are using the older schema type definition (your classes derive from the RealmObject base class), or you do not have nullability enabled, use the [Required] attribute if the list contains nullable reference types, such as string or byte[].

You can remove one or more elements from a RealmList within a write transaction:

• To remove one element from the list, pass the element to list.remove().

• To remove one element at a specified index in the list, pass the index to list.removeAt().

• To remove multiple contiguous elements from the list, pass the range to list.removeRange().

• To remove the last element from the list, call list.removeLast().

• To remove specific elements from a list that match a query, call list.removeWhere().

For the available methods to remove elements from a list, refer to the RealmList API reference.

You can remove one or more elements from a List within a write transaction. Call list.remove() with the index of the element you want to remove.

You can remove one or more elements in a single transaction from a RealmList:

• To remove one element from the list, pass the element to list.remove().

• To remove one element at a specified index in the list, pass the index to list.removeAt().

• To remove multiple elements from the list, pass the elements to list.removeAll().

You can also remove all list elements at once by calling list.clear().

In the following example, we have a Forest object with a list of Pond objects. We remove the list elements in a series of operations until the list is empty:

// Open a write transaction
realm.write {
    // Query for the parent forest object
    val forest = query<Forest>("name == $0", "Hundred Acre Wood").find().first()
    val forestPonds = forest.nearbyPonds
    assertEquals(5, forestPonds.size)
    // Remove the first pond in the list
    val removeFirstPond = forestPonds.first()
    forestPonds.remove(removeFirstPond)
    assertEquals(4, forestPonds.size)
    // Remove the pond at index 2 in the list
    forestPonds.removeAt(2)
    assertEquals(3, forestPonds.size)
    // Remove the remaining three ponds in the list
    forestPonds.removeAll(forestPonds)
    assertEquals(0, forestPonds.size)
}

In the following example, we have a Forest object with a list of Pond objects. We remove all list elements with the list.clear() method:

For the available methods to remove elements from a list, refer to the RealmList API reference.

You can remove one or more elements from a RLMArray within a write transaction:

• To remove one element at a specified index in the list, pass the index to removeObjectAtIndex.

• To remove the last element from the list, call removeLastObject.

You can also remove all list elements at once by calling removeAllObjects.

You can remove one or more elements from a List within a write transaction:

• To remove one element at a specified index in the list, pass the index to list.removeAt().

• To remove multiple contiguous elements from the list, pass the range to list.removeSubrange().

• To remove the first N elements from the beginning or end of a list, call the list.removeFirst() or list.removeLast() methods with an Int number of items to remove from the beginning or end of the list.

You can also remove all list elements at once by calling list.removeAll().

You can remove one or more elements from a List within a write transaction. Call list.remove() with the index of the element you want to remove.

You can delete a set element with erase(), or remove all elements from a set with clear().

You can remove one or more elements from a set within a write transaction.

Deleting an object from the database will remove it from any sets in which it existed. Therefore, a set of objects will never contain null objects. However, sets of primitive types can contain null values. If you do not want to allow null values in a set, then either use non-nullable types in the set declaration (for example, use ISet<double> instead of ISet<double?>). If you are using the older schema type definition (your classes derive from the RealmObject base class), or you do not have nullability enabled, you will need to use the [Required] attribute if the set contains nullable reference types, such as string or byte[].

You can remove one or more elements from a RealmSet within a write transaction:

• To remove one element from the set, pass the element to set.remove().

• To remove specific elements from a set that match a query, call set.removeWhere().

• To remove all elements from the set, call set.removeAll().

For the available methods to remove elements from a set, refer to the RealmSet API reference.

To remove a specific value from a set, pass the value to the <Realm.Set>.delete() method within a write transaction.

realm.write(() => {
  // remove the compass from playerOne's inventory by calling the
  // `delete()` method of the Realm Set object within a write transaction
  playerOne.inventory.delete("compass");
});

To remove all items from the set, run the <Realm.Set>.clear() method within a write transaction.

You can remove one or more elements in a single transaction from a RealmSet:

• To remove one element from the set, pass the element you want to delete to set.remove().

• To remove multiple elements from the set, pass the elements you want to delete to set.removeAll().

You can also remove all set elements at once by calling set.clear().

In the following example, we have a Frog object with a set of Snack objects. We remove the set elements in a series of operations until the set is empty:

// Open a write transaction
realm.write {
    // Query for the parent frog object
    val myFrog = query<RealmSet_Frog>("name == $0", "Kermit").find().first()
    val snackSet = myFrog.favoriteSnacks
    assertEquals(3, snackSet.size)
    // Remove one snack from the set
    snackSet.remove(snackSet.first { it.name == "Flies" })
    assertEquals(2, snackSet.size)
    // Remove the remaining two snacks from the set
    val allSnacks = findLatest(myFrog)!!.favoriteSnacks
    snackSet.removeAll(allSnacks)
    assertEquals(0, snackSet.size)
}

In the following example, we have a Frog object with a set of Snack objects. We remove all set elements with the set.clear() method:

For the available methods to remove elements from a set, refer to the RealmSet API reference.

You can remove one or more elements from a RLMSet in a write transaction.

• To remove one element from the set, call removeObject with the element you want to delete.

• To remove from the receiving set elements that aren't a member of another set, call intersectSet with the other set as an argument.

• To remove from the receiving set elements that are a member of another set, call minusSet with the other set as an argument.

You can remove all set elements at once by calling removeAllObjects.

You can delete specific elements from a MutableSet, or clear all of the elements from the set. If you are working with multiple sets, you can also remove elements in one set from the other set; see: Update a Set Property.

To remove a specific value from a set, pass the value to the <Realm.Set>.delete() method within a write transaction.

To remove all items from the set, run the <Realm.Set>.clear() method within a write transaction.

To delete a map key, pass the key name to erase().

You can remove dictionary keys and values within a write transaction.

You can remove keys and values from a RealmMap within a write transaction. To remove a key and its associated value, call map.remove(). To remove an element matching a query, call map.removeWhere().

For the available methods to remove dictionary keys and values, refer to the RealmMap API reference.

To delete members of a dictionary, use the dictionary.remove() method with an array of properties to remove from the dictionary.

You can remove RealmDictionary entries in a few ways:

• To remove the value but keep the key, set the key to null (the dictionary's value must be nullable)

• To remove the key and the value, pass the key to remove()

You can also remove all keys and values by calling clear().

In the following example, we have a Frog object with a dictionary of String values. We remove the dictionary elements in a series of operations until the dictionary is empty:

For the available methods to remove dictionary keys and values, refer to the RealmMap API reference.

You can remove RLMDictionary entries in a few ways:

• To remove the value but keep the key, set the key to null (the dictionary's value must be nullable)

• To remove the key and the value, pass the key to removeObjectForKey

• To remove keys specified by elements in a given array, pass the array to removeObjectsForKeys

You can also remove all keys and values by calling removeAllObjects.

You can delete map entries in a few ways:

• Use removeObject(for:) to remove the key and the value

• If the dictionary's value is optional, you can set the value of the key to .none to keep the key. This sets the key's value to nil but does not delete the key.

• Like a Swift dictionary, if you set the key value to nil, this deletes both the key and the value.

• If the value of a dictionary key is another object, and you delete the object, the key remains and its value is set to nil.

To delete members of a dictionary, use the dictionary.remove() method with an array of properties to remove from the dictionary.