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selectodataexpandodata-v4

OData V4: Is it possible to only select fields from a parent entity (i.e. navigation property)?

In OData V3, I can select just fields from parent/ancestor entities like this: http://services.odata.org/V3/Northwind/Northwind.svc/Order_Details(OrderID=10248,ProductID=11)?&$select=Product/Category/CategoryName&$expand=Product/Category

That query returns only CategoryName, it does not include any fields from Order_Details or Product. This behavior is very important to our application for performance reasons. Selecting all fields when we don't need them can have a significant impact on query performance.

There does not seem to be a way to accomplish the same in OData V4. The equivalent query returns all fields from Order_Details and Product http://services.odata.org/V4/Northwind/Northwind.svc/Order_Details(OrderID=10248,ProductID=11)?$expand=Product($expand=Category($select=CategoryName))

The closest I can get is to just select one field from each level, introduces a lot of complexity into our code, and it has been difficult to ensure that all queries (future and existing) adhere to this rule.

Solution

  • The closest I can get is to just select one field from each level, introduces a lot of complexity into our code, and it has been difficult to ensure that all queries (future and existing) adhere to this rule.

    Looks something like this:

    http://services.odata.org/V4/Northwind/Northwind.svc/Order_Details(OrderID=10248,ProductID=11)?$expand=Product($select=Category;$expand=Category($select=CategoryName))&$select=Product

    There is certainly a bit of added complexity here, but this was acceptable in my case.