The Derived Persistent Type Is Part Of a Flat Inheritance Hierarchy But Contains Properties Mapped To Not-Nullable Columns

This article is relevant to entity models that utilize the deprecated Visual Studio integration of Telerik Data Access. The current documentation of the Data Access framework is available here.

This error occurs when a derived persistent class is part of a flat inheritance hierarchy and contains properties mapped to not-nullable columns in the same time.

Solution

To resolve this error, set the 'allow nulls' attribute for all columns mapped to this class to True.

  1. Double-click the error to open the Validation Dialog.
  2. Apply the automatic fix for setting the 'allow nulls' attribute.

Further References