Delete Objects from relation¶

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

Using Untyped Objects

Backendless.Data.of( "TABLE-NAME" ).deleteRelation( 
      parentObject,
      relationColumnName,
      childrenArray )
  .then( function( count ) {
   })
  .catch( function( error ) {
   });

Custom Class/Function

Backendless.Data.of( DataTypeX ).deleteRelation( 
       parentObject,
       relationColumnName,
       childrenArray )
 .then( function( count ) {
  })
 .catch( function( error ) {
  });

where:

Argument	Description
`TABLE-NAME`	name of the table where the parent object is stored.
`DataTypeX`	reference to a JS function/class identifying the table. Name of the table must match the name of the function.
`parentObject`	The object for which the relation with the specified children will be deleted. When this argument is a plain JS object (for the "Untyped Objects" approach), it must contain the `"objectId"` property.
`relationColumnName`	name of the column identifying the relation. Relation between the parent object and the objects from the `childrenArray` array for the column in `parentObject` will be deleted.
`childrenArray`	an array of child objects for which the relation with `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 an object from the Person table 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 Untyped Objects

var parentObject = { objectId:"41230622-DC4D-204F-FF5A-F893A0324800"};
var childObject1 = { objectId:"XXXX-XXXX-XXXX-XXXXX" };
var childObject2 = { objectId:"ZZZZ-ZZZZ-ZZZZZ-ZZZZZ" };
var children = [ childObject1, childObject2 ];

Backendless.Data.of( "Person" ).deleteRelation( parentObject, "address", children )
 .then( function( count ) {
    console.log( "relation has been deleted" );
  })
 .catch( function( error ) {
    console.log( "server reported an error - " + error.message );
  });

Custom Class/Function

function Person {
  // properties of Person defined here
}

function Address {
  // properties of Address defined here
}

var personObject = // personObject retrieval is out of scope in this example
var addressObject1 = // addressObject retrieval is out of scope in this example
var addressObject2 = // addressObject retrieval is out of scope in this example
var addressCollection = [ addressObject1, addressObject2 ];

Backendless.Data.of( Person ).deleteRelation( personObject, "address", addressCollection )
  .then( function( count ) {
     console.log( "relation has been deleted");
   })
  .catch( function( error ) {
     console.log( "server reported an error - " + error.message );
   });