Entity Framework
http://www.entityframeworktutorial.net/entity-relationships.aspx
http://www.entityframeworktutorial.net/code-first/dataannotation-in-code-first.aspx
http://www.entityframeworktutorial.net/code-first/entitytypeconfiguration-class.aspx
http://www.entityframeworktutorial.net/code-first/configure-one-to-one-relationship-in-code-first.aspx