Adding list to Backendless.User

Server Code
1

i made a query to get a list of orders of user
//user
var newPerson=new Backendless.User()
newPerson.objectId=user[“objectId”];
newPerson.firstName= user[ “firstName” ]
newPerson.lastName= user[ “lastName” ]
var whereClause = “ownerId=’”+user[“objectId”]+"’";
var queryBuilder = Backendless.DataQueryBuilder.create().setWhereClause(whereClause);
//storing the result of query in newPerson.orders
newPerson.orders=Backendless.Data.of( “order” ).find( queryBuilder )
.then( function( orders) {
return orders
})
.catch( function( fault ) {

});
return newPerson;
output:
{
“___jsonclass”: “Users”,
“firstName”: “aadel”,
“lastName”: “kanso”,
“orders”: {},
“___class”: “Users”,
“objectId”: “F6AD65BB-D2FD-099F-FF20-D68A4AA76600”,
}
the query it self return a list of orders but whenever i want to store this list in newPerson.orders the result become {} as shown in output

2

Hello @adel_kasno

In order to establish relationship between objects you need to use set/addRelation API
https://backendless.com/docs/js/data_set_relation_with_objects.html

Regards, Vlad

3

there isn’t a relationship , i’m working with ownerId
please if you can re-read my problem
its about to store the return object coming from Backendless.Data.of( “order” ).find( queryBuilder )

4

Hi Adel,

From what I understood, when you store newPerson you also want to store the orders of that person. Since the order objects are stored in a separate from the person table (the order table), it becomes a relation in the Backendless lingo. So @vladimir-upirov’s answer is actually correct.

Regards,
Mark

5

I’m trying to get objects not storing them
i set up the relationship…
and i turned on “AutoLoad”
so when retrieving person the orders also being retrieved
but right now i want to retrieve items and ther is orderId in items table
so how can i retrive person orders items
the structure is like this
person(order id 1:1)
order()
items(order_id 1:N)

Regards

6

No problem, I just need a little help so I can understand your schema better. If I understood correctly, you have the following tables:

  • person
  • order
  • items

The person table has a one-to-one relationship to order.
The items table has a one-to-many relation to order.

Am I correct so far?

And what you’re asking is how to retrieve items for some specific person’s order. Is that also correct?

Regards,
Mark

7

Correct this is the relation and that’s what i’m trying to do

8

Once you know order’s objectId, you can structure the following query (I assume the name of the relation column between items and order is order_id:

var whereClause = "order_id.objectId='" +  VALUE_OF_ORDER_OBJECTID  + "'";
var queryBuilder = Backendless.DataQueryBuilder.create().setWhereClause(whereClause);
newPerson.orders=Backendless.Data.of( "items" ).find( queryBuilder )
.then( function( items ) {
  return items
})
.catch( function( fault ) {

});

This will retrieve all the items for a particular order.

1 Like
9

method find returns an instance of Promise,
so to assign the items list to newPerson as orders you have to use async/await or do it inside the then function

newPerson.orders = await Backendless.Data.of( "items" ).find( queryBuilder )

or

Backendless.Data.of( "items" ).find( queryBuilder )
.then( function( items ) {
  newPerson.orders = items
})
.catch( function( fault ) {

});
1 Like
10

Problem solved ,
yes find return a Promise so i must use async/await
Thank you @mark-piller @vladimir-upirov
i ended up with this
async function myFx(user){
var newPerson=new Backendless.User()
newPerson.objectId=user[“objectId”];
newPerson.firstName= user[ “firstName” ]
newPerson.lastName= user[ “lastName” ]
var whereClause = “order_id.objectId=’” + user.order.objectId + “’”;
var queryBuilder = Backendless.DataQueryBuilder.create().setWhereClause(whereClause);
newPerson.orders=await Backendless.Data.of( “items” ).find( queryBuilder )
.then( function( items ) {
return items
})
.catch( function( fault ) {

});
}
also the @vladimir-upirov the second code doesn’t work , but as i said async/await work as expected
Regards

11

glad to hear that!

the second option doesn’t work because this is async code

Backendless.Data.of( "items" ).find( queryBuilder )
.then( function( items ) {
  newPerson.orders = items // it will be invoked after this: newPerson.orders === undefined 
})

newPerson.orders === undefined // this is expected behaviour, and it will be invoked before newPerson.orders = items

btw, you do not need to specify then if you use await, just use

newPerson.orders=await Backendless.Data.of( “items” ).find( queryBuilder )

you can read more about async/await here https://javascript.info/async-await

Regards, Vlad

12

Thanks for informing me, i’m new at async await but i will read more about it