SAP MDK - Entities, Navigations and Fields

[vhsbc92]

Hello community,

I would like to share an issue I encountered with entities and their navigation fields.

I have two entities:

• cust_Turmas: Retrieves data from a class.
• cust_Instrutores: Retrieves data from instructors.

There is also a navigation from cust_Turmas to cust_Instrutores, which is called cust_Inst1Nav.

Here is the filter used to retrieve the data using OData:

$select:externalCode,externalName,cust_Inst1Nav/cust_fname,cust_Inst1Nav/cust_lname
$expand:cust_Inst1Nav
$filter:externalCode eq 235

The URL parameter is:

<BASE_URL>/?$select=externalCode,externalName,cust_Inst1Nav/cust_fname,cust_Inst1Nav/cust_lname&$expand=cust_Inst1Nav&$filter=externalCode eq 235

The data retrieved by the query is:

{
  "@odata.context": "$metadata#cust_Turmas",
  "value": [
    {
      "externalCode": "235",
      "externalName": "Course name",
      "cust_Inst1Nav": {
        "externalCode": "123",
        "cust_fname": "Victor",
        "cust_lname": "Cardoso"
      }
    }
  ]
}

I thought I could simply call the navigation fields as I do with the main entity. For example:

• {externalCode} = Retrieves 235
• {cust_Inst1Nav/cust_fname} = should retrieve Victor, but instead, it either returns blank or doesn’t exist.

However, the navigation fields are not being retrieved.

Is there something I'm missing?

This is my page:

page with header to show only one record

Here is my Target object configuration detailed.

my Target configurations

 I can see the fields inside entity "cust_Turmas" its navigation "cust_Inst1Nav" when I want to set a field value in my objects.

 I've created a rule to get me some clues and put in a field:

export default function checkEmpty(context) {
    let binding = context.binding;

    if (binding.cust_Inst1Nav) {
        if (binding.cust_Inst1Nav.cust_lname) {
            return binding.cust_Inst1Nav.cust_lname;
        } else {
            return 'No Last Name Available';
        }
    } else {
        return 'cust_Inst1Nav not available';
    }
}

The result is: cust_Inst1Nav not available 

I appreciate any comments/suggestions.

[vhsbc92]

@bill_froelich 

I’m speechless... incredible! Here's what I did to solve the issue:

I went to downloadOffline.action and InitializeOffline.action and added the expand I needed. After doing that, the previously blank fields were populated with the expected data.

Now I can see the data in the Object Header.

Thanks a lot! I'm learning a lot with you and all community's posts and members.

[bill_froelich]

Depending on the use case and data you can also included that entity set referred to by the navigation property rather than including it via the $expand. This will make all the data in that entity set available not just the expanded entries from the nav link.

[vhsbc92]

I got your point, but I'm not sure how and where I can do it. Would you mind to send a screenshot/file, please?

[bill_froelich]

Add another Defining Request to the list that is the EntitySet that the cust_Inst1Nav points to and remove the $expand from the cust_Turmas query

[vhsbc92]

Got it, thanks!!