ASP.NET MVC 4 Multiple Foreign Keys Referencing Single Parent Entity
asp.net-mvc, entity, foreign-keys, poco
Solution
By default, Entity Framework has a Cascade on Delete convention. When two entities have foreign keys to each other, it causes a circular reference and Cascade on Delete can't be applied to both entities.
The simplest solution is to remove the cascade on delete convention, and apply it on a case by case basis.
Problem
I am trying to develop an ASP.NET MVC 4 application where players can be rated according to their Offence, Defence and Assist skills. Offence, Defence and Assist are foreign keys on Player table referencing the same lookup table - Rating. I have the following parent entity: ``` public class Rating { public int Id { get; set; } public string Name { get; set; } public virtual ICollection<Player> Players { get; set; } } ``` And child entity: ``` public class Player { public int Id { get; set; } public string Name { get; set; } public int OffenceRatingId { get; set; } [ForeignKey("OffenceRatingId")] public virtual Rating OffenceRating { get; set; } public int DefenceRatingId { get; set; } [ForeignKey("DefenceRatingId")] public virtual Rating DefenceRating { get; set; } public int AssistRatingId { get; set; } [ForeignKey("AssistRatingId")] public virtual Rating AssistRating { get; set; } } ``` Building and scaffolding went fine but when I run the app, I get the following error: ``` Introducing FOREIGN KEY constraint 'FK_dbo.Players_dbo.Ratings_DefenceRatingId' on table 'Players' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints. ``` I am new to MVC and have no idea what I am missing here. Any help with this will be greatly appreciated. Thanks.