Delete Objects from relation¶

The API removes specific objects from a relationship with their parent.

Method¶

Using Map

Future<int> Backendless.data.of("TABLE-NAME").deleteRelation(
                    String parentObjectId, 
                    String relationColumnName, 
                   {List<String> childrenObjectIds, 
                    String whereClause});

Custom Class

Future<int> Backendless.data.withClass<E>(). deleteRelation(
                     String parentObjectId, 
                     String relationColumnName, 
                    {List<String> childrenObjectIds, 
                     String whereClause});

where:

Argument	Description
`TABLE-NAME`	Name of the table where the parent object is stored.
`E`	Dart class of the parent object. The class name identifies the table where the parent object is stored.
`parentObjectId`	The ID of an object for which the relation with the specified children will be deleted. When this argument is an instance of `Map` (for the map-based approach), it must contain the `"objectId"` property.
`relationColumnName`	Name of the column identifying the relation. Relationship between the specified objects from the `children` collection will be deleted for the column in `parentObject`.
`childrenObjectIds`	A collection of child object IDs for which the relationship with the `parentObject` will be deleted.

Return Value¶

Number of child objects for which the relationship has been deleted.

Example¶

The example below deletes a relation between a Person object and its children. The child objects are referenced explicitly in the API call (see the object IDs in the collection as "XXXXX-XXXXX-XXXXX-XXXXX" ``and`` "ZZZZ-ZZZZ-ZZZZZ-ZZZZZ").The relation column is address.

Using Map

Map parentObject = // parentObject retrieval is out of scope in this example
Map childObject1 = // childObject retrieval is out of scope in this example
Map childObject2 = // childObject retrieval is out of scope in this example

Backendless.data.of("Person"). deleteRelation(parentObject['objectId'], "address", 
  children: [childObject1['objectId'], childObject2['objectId']]).then((response) {
    // relation has been deleted
});

Custom Class

Person personObject = // personObject retrieval is out of scope in this example
Address addressObject1 = // addressObject retrieval is out of scope in this example
Address addressObject2 = // addressObject retrieval is out of scope in this example

Backendless.data.withClass<Person>(). deleteRelation(personObject.objectId, "address", 
  children: [addressObject1.objectId, addressObject2.objectId]).then((response) {
    // relation has been deleted
});