Entity Framework EDMX Invalid Multiplicity?

Question

I seem to be having trouble with database first multiplicity within the design. I am using EF v5.0

I have two db entities with the following (psuedo classes for example):

entity {
    long Id; //PK
    bool myProp;
}

entity_detail {
    long entityID; //FK to entity.Id
    string name;
    datetime entered;
}

When I update the model from the database it correctly generates these classes in the .tt, however, it puts the entity_detail into an ICollection<entity_detail> in the entity class.

This is due to the multiplicity, when I change the multiplicity from Many (*) to Zero or One (0..1) within the EDMX, it will error out and force me to use Many (*)

The issue with this scenario is that the entity_detail should ONLY be generated if myProp is set to false (to avoid redundant data in db)

Thus being a 0..1, any idea on how to set this up from the database perspective to get the EDMX to update it to 0..1 on the entity end and 1 on the entity_detail end?

Thanks in advance!

Answer 1

For anyone looking for the answer, the correct setup was to make the foreign key (entityID) column on the entity_detail object also a primary key.

This way it would be unique but only be required if it exists (0..1)

Hope this helps!