Multiple Foreign Key for Same table in Entity Framework Code First

Dogan Can Topal Published at Dev

Dogan Can Topal

I have two entities in my application and I populated the database with Entity Framework Code First. There are two Employee id in the Task entity; one of them forRequirerEmploye, others for RequestedEmployee. When make update-database in package manager console I get error like this:

Introducing FOREIGN KEY constraint 'FK_dbo.Tasks_dbo.Employees_DemandingEmployeeID' on table 'Tasks' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints.

My Task Class:

    public int ID { get; set; }
    public int DemandingEmployeeID { get; set; }
    public int RequestedEmployeeID { get; set; }



    [ForeignKey("DemandingEmployeeID")]
    [InverseProperty("DemandingTasks")]
    public virtual Employee DemandingEmployee { get; set; }

    [ForeignKey("RequestedEmployeeID")]
    [InverseProperty("RequestedTasks")]

    public virtual Employee RequestedEmployee { get; set; }

My Employee Class:

    public int ID { get; set; }

    public virtual ICollection<Task> DemandingTasks { get; set; }    
    public virtual ICollection<Task> RequestedTasks { get; set; }

My Context:

   modelBuilder.Entity<Task>().HasRequired(m => m.DemandingEmployee).WithMany(m => m.DemandingTasks).HasForeignKey(m => m.DemandingEmployeeID);
        modelBuilder.Entity<Task>().HasRequired(m => m.UpdatedEmployee).WithMany(m => m.UpdatedTasks).HasForeignKey(m => m.UpdatedEmployeeID);

Fabio Luz

The problem is that you have multiple paths of cascade deletes, that could end trying to delete the same row in the database. To understand more about this error, take a look at https://support.microsoft.com/en-us/kb/321843. Follow the steps above to solve the problem.

Change your class:

public int ID { get; set; }
public int DemandingEmployeeID { get; set; }
public int RequestedEmployeeID { get; set; }

public virtual Employee DemandingEmployee { get; set; }
public virtual Employee RequestedEmployee { get; set; }

Change your context:

modelBuilder.Entity<Task>()
     .HasRequired(m => m.DemandingEmployee)
     .WithMany(m => m.DemandingTasks)
     .HasForeignKey(m => m.DemandingEmployeeID)
     .WillCascadeOnDelete(false);

modelBuilder.Entity<Task>()
     .HasRequired(m => m.RequestedEmployee)
     .WithMany(m => m.RequestedTasks)
     .HasForeignKey(m => m.RequestedEmployeeId)
     .WillCascadeOnDelete(false);

modelBuilder.Entity<Task>()
    .HasRequired(m => m.UpdatedEmployee)
    .WithMany(m => m.UpdatedTasks)
    .HasForeignKey(m => m.UpdatedEmployeeID)
    .WillCascadeOnDelete(false);

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edited at2021-02-23

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