Problem changing a value from nullable to non-nullable.

Question

Hello,

In my database I add an int foreign key that was allow null values. I changed that so that it does not accept null values.

Since then, when I run my C# Winforms application, I get the exception:

Model1.msl(15,10) : error 3031: Problem in mapping fragments starting at line 15:Non-nullable column Addresses.addr_Contact_Id in table Addresses is mapped to a nullable entity property.

when I select data.

 

In my Model1.edmx file, I have used 'Update Model From Database ...'

--> no change

 

I checked the field in Model1.edmx, it has 'Nullable = none', so I changed it manually to 'Nullable = false'.

But when I do that all my datasources based on this edmx files say '[datasource] is no longer availble. Verify the class name is correct and the reference to this class is still valid.

 

So, how do I change the nullable state of a value in from the DB to the app ?

 

Thank you for your help.

Answer 1

Delete the offending table from the edmx gui and then update using the wizard (expand tables) and add your updated table.  Rebuild your solution.

Answer 2

Thank you.

This was useful just right now, but doing this, you can lose custom Navigation Properties ...

Answer 3

If you create your relationships in the database it will keep/apply them when you update the table.