Single Step Retrieval¶

Important

Single Step Retrieval loads only a partial set of the related objects (default size of the retrieved related collection is 10). To load additional related objects, use the Relation Paging API .

This approach allows retrieval of a partial set of the related objects along with the parent object in a single findor findById request. Each relationship property (column) must be uniquely identified by name using the API documented below.

Retrieving a specific object with relations¶

Using Untyped ObjectsCustom Class/Function

Non-blocking call:

Backendless.Data.of( "TABLE-NAME" ).findById( "XXXX-XXXX-XXXX-XXXX", {                                              
 relations:["relationA", "relationB"] })
 .then( function( result ) {
  })
 .catch( function( error ) {
  });

Blocking call:

var obj = Backendless.Data.of( "TABLE-NAME" ).findByIdSync( {objectId:"XXXX-XXXX-XXXX-XXXX",
                                                            { relations:["relationA", "relationB"] } } );

Non-blocking call:

Backendless.Data.of( DataTypeX ).findById( {objectId:"XXXX-XXXX-XXXX-XXXX",
                                            loadRelations:"relationA,relationB" })
 .then( function( result ) {
  })
 .catch( function( error ) {
  });

Blocking call:

var obj = Backendless.Data.of( DataTypeX ).findById( {objectId:"XXXX-XXXX-XXXX-XXXX",
                                                      loadRelations:"relationA,relationB" } );

Retrieving a collection of objects with relations¶

var queryBuilder = Backendless.DataQueryBuilder.create();
queryBuilder.setRelated( [ "RELATED-PROPERTY-NAME", 
                           "RELATED-PROPERTY-NAME.RELATION-OF-RELATION" ] );

Then load data using the constructed queryBuilder object with:

Using Untyped ObjectsCustom Class/Function

Non-blocking call:

Backendless.Data.of( "TABLE-NAME" ).find( queryBuilder )
 .then( function( objectCollection ) {
  })
 .catch( function( error ) {
  });

Blocking call:

var objectCollection = Backendless.Data.of( "TABLE-NAME" ).findSync( queryBuilder );

Non-blocking call:

Backendless.Data.of( DataTypeX ).find( queryBuilder )
 .then( function( objectCollection ) {
  })
 .catch( function( error ) {
  });

Blocking call:

var objectCollection = Backendless.Data.of( DataTypeX ).findSync( queryBuilder );

where

Argument	Description
`RELATED-PROPERTY-NAME`	Name of a related property to load. For example, if table `Person` has a relation "`homeAddress`" pointing to an object in the `Address` table, the value would be "`homeAddress`". The syntax allows to add relations of relations. For example, if the same `Address` table has a relation "`country`" pointing to the `Country` table, then "`homeAddress.country`" would instruct the related `Country` object to be loaded as well.
`queryBuilder`	An instance of the `Backendless.DataQueryBuilder` class. The class is used to identify related properties for relation retrieval.
`TABLE-NAME`	Name of the table where the data should be retrieved from
`DataTypeX`	Reference to a class/function which identifies a table where the data should be loaded from.