remove foreign key property cause an exception

Question

I don't want to use foreign key association to CompanyType (member that will hold the foreign key id) but prefer to use navigation property. So I removed the CompanyTypeId.

I get this exception that relates the relationship between entity Company and CompanyType:

Error 5: The element 'Principal' in namespace 'http://schemas.microsoft.com/ado/2008/09/edm' has incomplete content. List of possible elements expected: 'PropertyRef' in namespace 'http://schemas.microsoft.com/ado/2008/09/edm'.

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How can I remove those id's from the POCOs without getting the exception?

well typically you can't remove CompanyTypeId until you remove the constraint making it a foreign key to ID. Once that constraint is removed, then you can remove the CompanyTypeId from Company. — Tyler Ferraro, Apr 21 '11 at 22:21
@Tyler Ferraro: But if I'll remove the FK constraint - does it know how to load the navigation properties? — Naor, Apr 21 '11 at 22:24

score 8 · Accepted Answer · edited May 23 '17 at 10:30

This is the difference between Foreign key association and Independent association. Both associations use navigation properties but only Foreign key association uses FK property as well. You can either remove them globally as @Robbie mentioned or you can change the type manually for selected relation.

Select the relation in entity framework designer
In properties remove Referential constraints
Go to Mapping window and map the relation

Here is the screen shot from one of my testing application with one-to-many relation between Order and OrderLine entities:

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As you can see there is no OrderId in the OrderLine entity and referential constraints of the relation are empty. Also mapping of the relation is specified.

BUT you can't never remove Id from CompanyType. Ids (PKs) are mandatory. You can only change its accessibility in its properties.

How can I do Insert (determine the CompanyTypeId) if I remove the CompanyTypeId from Company entity? — Naor, Apr 25 '11 at 21:28
@Noar: You must assign the navigation property `company.CompanyType = ...;` — Ladislav Mrnka, Apr 25 '11 at 21:33

score 4 · Answer 2 · answered Apr 21 '11 at 23:20

4

When you imported in your Model from your DB you are asked if you want to:

"Include Foreign key columns in the model" you need to switch this off.

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answered Apr 21 '11 at 23:20

Robbie Tapping

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If I'll remove the foreign key constraint from the entity data model - doed the ef will know to load the navigation properties?? – Naor Apr 22 '11 at 00:44
The Entity Propertys will still be created, it is on the FK columns that wont be :) – Robbie Tapping Apr 22 '11 at 00:58
Rescued from EF inheritance based errors bafflement. Thank you. – Neil Thompson Jul 24 '13 at 15:31

remove foreign key property cause an exception

2 Answers2