Question

How can I make a constraint on Entity Framework to read a foreign key relation from table cars to vehicle (for example) as 0..1 -> 1 instead of * -> 1?

I have tables

create TABLE [dbo].[Vehicles](
  [Id] [int] IDENTITY(1,1) NOT NULL primary key,
  <rest of the columns>
)

create TABLE [dbo].[Cars](
  [Id] [int] NOT NULL,
  <rest of the columns>
)

and foreign key:

alter table [Cars] add foreign key(id) references [Vehicles](id)

when I create a model from the DB, it is created as * -> 1 an I cant change:

I know I manually change the association between the two entities but it doesn’t matter because it doesn’t change the constraint

I need to do that to set the baseType property of Cars to Vehicle to Implement a Inheritance.

Currently I’m getting this error:

Multiplicity is not valid in Role ‘BoatsTPT’ in relationship
‘FK__BoatsTPT__Id__117F9D94’. Because the Dependent Role refers to the
key properties, the upper bound of the multiplicity of the Dependent
Role must be 1.

Answer 1

You must first make Id column in your Cars table a primary key otherwise it is not one-to-one relation.