OData returning children, but no Breeze property / method available on parent entity

Question

I am "successfully" executing a breeze query against an asp.net web api ODATA service, but there doesn't seem to be any children, even though the response has the children in it.

query: var query = breeze.EntityQuery.from('Transactions') .take(20) .orderBy('Transaction_Timestamp desc') .expand('Items');

How do I access the children? I have tried .Items, .Items(), .Item, .Item(), there is no property or method there. On the service side, I verified that there are navigation properties from Transaction to Items (Transaction.Items), and Items.Transaction. And, as I said, the http response from the service has all of the children's data.

Where can I look to see where the problem might be?

Breeze config:

    breeze.config.initializeAdapterInstance('dataService', 'webApiOData', true);

    $http.defaults.headers.put = {
        'Access-Control-Allow-Origin': '*'
    };

    new breeze.ValidationOptions({ validateOnAttach: false }).setAsDefault();

    var metadataStore = createMetadataStore();
    etc.

My Transaction class:

 public partial class Transaction
    {
        public Transaction()
        {
            this.Discounts = new HashSet<Discount>();
            this.Items = new HashSet<Item>();
            this.Tenders = new HashSet<Tender>();
        }

        public System.Guid Id { get; set; }
       ...

        public virtual ICollection<Item> Items { get; set; }

    }

My Item class:

public partial class Item
{
    public System.Guid Id { get; set; }
    public System.Guid Transaction_Id { get; set; }

   ...

    public virtual Transaction Transaction { get; set; }
}

Would this not be enough?

odata/$metadata for Item entity:

<EntityType Name="Item">
<Key>
<PropertyRef Name="Id"/>
</Key>
<Property Name="Id" Type="Edm.Guid" Nullable="false"/>
<Property Name="Transaction_Id" Type="Edm.Guid" Nullable="false"/>
... (omitted fields)

<NavigationProperty Name="Transaction" Relationship="TransactionService.Models.TransactionService_Models_Item_Transaction_TransactionService_Models_Transaction_TransactionPartner" ToRole="Transaction" FromRole="TransactionPartner"/>
</EntityType>

This is data returned in the Transactions.Expand('Items') breeze query:

{
  "odata.metadata":"http://localhost:49858/odata/$metadata#Transactions","value":[
    {
      "odata.type":"TransactionService.Models.Transaction","odata.id":"http://localhost:49858/odata/Transactions(guid'f93805cf-cc80-4d2e-9d9e-97df9c21c622')","[email protected]":"http://localhost:49858/odata/Transactions(guid'f93805cf-cc80-4d2e-9d9e-97df9c21c622')/Discounts","[email protected]":"http://localhost:49858/odata/Transactions(guid'f93805cf-cc80-4d2e-9d9e-97df9c21c622')/Shift","[email protected]":"http://localhost:49858/odata/Transactions(guid'f93805cf-cc80-4d2e-9d9e-97df9c21c622')/Tenders","[email protected]":"http://localhost:49858/odata/Transactions(guid'f93805cf-cc80-4d2e-9d9e-97df9c21c622')/Items","Items":[
        {
          "odata.type":"TransactionService.Models.Item","odata.id":"http://localhost:49858/odata/Items(guid'511348d7-2886-4b13-ad7e-0eeb2a11bd85')","[email protected]":"http://localhost:49858/odata/Items(guid'511348d7-2886-4b13-ad7e-0eeb2a11bd85')/Transaction","[email protected]":"Edm.Guid","Id":"511348d7-2886-4b13-ad7e-0eeb2a11bd85","[email protected]":"Edm.Guid","Transaction_Id":"f93805cf-cc80-4d2e-9d9e-97df9c21c622","[email protected]":"Edm.DateTime","Updated":"2014-05-06T20:30:30.657","[email protected]":"Edm.Int16","Ordinal":1,"Item_Type":"item      ","Item_Number":"39                  ","Parent_Ordinal":null,"[email protected]":"Edm.Byte","Modifier":0,"Description":"Cinnamon Coffee Cake","Item_Serial":null,...

etc...

Can you show your models and their relationships? Remember that in your model definitions you need to have a proper relationship between the two models so that Breeze knows when Items show up in the JSON that it is of type Item to map it properly. — PW Kad
I may not get your questions right. So your point is: you can get the right response, but you cannot read the expanded items out with Breeze Api? — zoe

António Sérgio Simões António Sérgio Simões · Accepted Answer · 2014-05-09T15:25:46

Can you show us your Transaction and Items model classes? I bet you are missing a foreign key there...

Note that just setting the navigation property in your model will not suffice for Breeze to detect the association.

Example:

    //This will not work

    public class Transaction
    {
         public Transaction()
         {
            Items = new HashSet<Items>();
         }
         public int Id {get;set;}
         public virtual ICollection<Items> Items {get;set;}
    }

    public class Items
    {
       public int Id {get;set;}
       public Transaction Transaction {get;set;}
    }

Everything looks ok, right? Wrong.

Why?

Because the Items class doesn't have a FK property towards the parent. You'd need to modify the class to look like this:

   public class Items
   {
       public int Id {get;set;}
       public int TransactionId {get;set;} // FK Property

       public Transaction Transaction {get;set;}
   }

Not saying this is your problem, but you should confirm that you have FK Properties set properly in order to Breeze work.

Here's why: http://www.breezejs.com/documentation/navigation-properties#foreignkeys

OData returning children, but no Breeze property / method available on parent entity

3 Answers