Implementing one-to-zero-or-one relation in SQL Server

Question

I\'m using Entity Framework 4.1 database first approach. I\'ve used legacy database. In my edmx file which created entity classes based on tables in the legacy database, the

Answer 1

If the database tables are already designed with a 1:1 relationship (or a 1:0-1), then EF will work with it just fine, although it will pluralize the child table's name (if you let it pluralize).

The basic approach is to create a foreign key (as if you were making a 1:many relationship), then put a unique index on the foreign key field. Is that what you are aiming to accomplish?

This might help, too: Designing 1:1 and 1:m relationships in SQL Server .

On a side note, 1-1 relationships are often not necessary and/or a symptom of a database design that needs rethinking. However, it sounds like you inherited the design... I know all about that!