Cascade Delete Rule in EF 4.1 Code First when using Shared Primary Key Association

Question

I implemented a bidirectional 1:1 relationship based on this answer:

Primary /Foreign Key in Entity Framework

I define the bidirectional relation this way:

Answer 1

Also, you can use [Required] Attribute, and it will automatically set the delete rule to "CASCADE" mode in related relationship. (and also set "Allow Null" property of that entity to "false" in DB)