Entity Framework Core Cookbook - Second Edition

Mapping discriminator columns

You cannot map discriminator columns.

Problem

When you have a class hierarchy that you want to map to a database table using the Table per class hierarchy/Single table inheritance pattern, this table will make use of a discriminator column to figure out the class that each record refers to; this is because the same table will hold records for any of the derived classes of the hierarchy. You may be tempted to add a property for this discriminator column, but you will not succeed, because discriminator columns cannot be mapped.

How to solve it…

You simply cannot map the discriminator column as a property, because doing so might cause the type of the stored record to change from one class to another, and Entity Framework ...