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Editorial Team
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Asked: 2026-05-23T03:02:14+00:00

I have a data model as follows: A Customer has Products and Payment Methods.

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I have a data model as follows:

Data Model

A Customer has Products and Payment Methods. Each Product can be assigned any or all of the Customer’s Payment Methods, with one set as default.

Foreign Keys are:

Customer.CustomerId => Product.CustomerId
Customer.CustomerId => PaymentMethod.CustomerId
Product.ProductId => ProductPaymentMethod.ProductId
PaymentMethod.PaymentMethodId => ProductPaymentMethod.PaymentMethodId

I want to customise this model for presentation purposes, Customer to have a collection of Payment Methods and a collection of Products. Products to have a collection of ProductPaymentMethods which inherit from PaymentMethod.

I deleted the association between PaymentMethod and ProductPaymentMethod, added an inheritence from PaymentMethod to ProductPaymentMethod and deleted PaymentMethodId from ProductPaymentMethod.

This is now my model:

Presentation Model

When I save the model or build the project I get 2 errors:

Error 3002: Problem in mapping
fragments starting at line
226:Potential runtime violation of
table ProductPaymentMethod’s keys
(ProductPaymentMethod.ProductPaymentMethodId):
Columns
(ProductPaymentMethod.ProductPaymentMethodId)
are mapped to EntitySet
PaymentMethods’s properties
(PaymentMethods.ProductPaymentMethodId)
on the conceptual side but they do not
form the EntitySet’s key properties
(PaymentMethods.PaymentMethodId).

and

Error 3003: Problem in mapping
fragments starting at line 226:All the
key properties
(PaymentMethods.PaymentMethodId) of
the EntitySet PaymentMethods must be
mapped to all the key properties
(ProductPaymentMethod.ProductPaymentMethodId)
of table ProductPaymentMethod.

What am I doing wrong?

EDIT: Having done some further Googling, I have found several solutions, most of which don’t quite fit this scenario. Most talk about inheritance requiring a 1-1 not 1-many relationship. However, because of the Customer to Product 1-many relationship, the model requires a 1-many between PaymentMethod and ProfilePaymentMethod. Is it not possible to do what I am attempting?

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1 Answer

  1. Editorial Team

    My only answer to this so far is to have some manually created POCO classes for presentation and a Mapper class to turn my data entity into a presentation entity

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