FireDAC Components for OData

Build 23.0.8839


Whether you need to specify the base entity's key to query navigation property views.


property SupportsExpand: Boolean;

Data Type


Default Value



This connection property is primarily used with limited OData APIs; it determines whether navigation properties can be retrieved from the base entity set. In OData, navigation properties link a base entity to a related entity or a collection of related entitites.

For more on navigation properties, see Data Model.

Working with Limited APIs

In OData, the $expand parameter is used to expand specified navigation properties when requesting data from a given entity set. In SQL, this makes it possible to execute a SELECT * to a navigation property view.

If $expand is not supported, a different request must be made to retrieve a navigation property, one that specifies the primary key of the base entity set. This API restriction is reflected in SQL: You will need to specify the base entity's primary key in the WHERE clause.

For example, consider two entities with a one-to-many relationship in the Northwind sample service, Categories and Products. In OData, the Products associated with a given Category could be represented as a navigation property on the base Category entity set. The component models the Products navigation property as a Categories_Products view.

If $expand is not supported, use a query like the following to this view:

SELECT       * 
FROM         Categories_Products
WHERE        (Categories_CategoryID = 1)

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Build 23.0.8839