c# - Entity Framework - Add Navigation Property Manually

Question

I generated an Entity Framework Model (4.0) from my database. I did not design the database and do not have any control over the schema, but there are a few tables that do not have foreign key constraints defined, but there is an implicit relationship defined.

For example:

I have a table called People that has the following columns: GenderID RaceID

There are tables for both Gender and Race but there is no foreign key in the People table.

When I imported the model it did not add Navigation Properties for these relationships. I tried to add it manually but From Role and To Role are disabled. I'm not sure how to add the relationship myself. How do I do this?

Answer 1

Yup - it's not that straightforward.

Here's what you do:

1 - Right click on the designer, Add -> Association

2 - Setup the association and cardinalities (People *..1 Gender, People *..1 Race)

3 - Go into the Model Browser -> Associations

4 - Right click on your newly created associations, click Properties

5 - Here you need to setup the endpoints for the key and cascade options. Make sure you get the endpoints correct. You can also setup a referential constraint here for your implicit navigational property.

6 - Map the navigational property to the relevant tables/fields.

7 - Validate your model, cross your fingers.

Hope this helps.