Data Query¶
Data service find operation can accept an argument with additional options instructing the server to sort data, retrieve paged results and return related child objects. The example below demonstrates the usage of the data query argument in versions 3.x and 5.x:
Version 3.x¶
var contactStorage = Backendless.Data.of( "Contact" ); var dataQuery = new Backendless.DataQuery(); // set where clause dataQuery.condition = "age > 30"; // prepare options object (for relations, sorting, pageSize and offset) dataQuery.options = {} dataQuery.options.relations:[ "address","preferences" ] }; // request sorting dataQuery.options.sortBy = [ "name" ] // set offset and page size dataQuery.options.pageSze = 20; dataQuery.options.offset = 40; contactStorage.find( dataQuery, new Backendless.Async( function( contactsCollection ) { console.log( "retrieved " + contactsCollection.data.length + " contacts" ); } ));
Version 5.x¶
var contactStorage = Backendless.Data.of( "Contact" ); var queryBuilder = Backendless.DataQueryBuilder.create(); // set where clause queryBuilder.setWhereClause( "age > 30" ); // request related objects for the columns queryBuilder.setRelated( [ "address", "preferences" ] ); // request sorting queryBuilder.setSortBy( [ "name" ] ); // set offset and page size queryBuilder.setPageSize( 20 ); queryBuilder.setOffset( 40 ); contactStorage.find( queryBuilder ) .then( function( contactsArray ) { console.log( "retrieved " + contactsArray.length + " contacts" ); });
Additional resources: