Using the data annotation Required like so:
[Required]
public int somefield {get; set;}
Will set somefield to Not
Just omit the [Required] attribute from the string somefield property. This will make it create a NULLable column in the db.
To make int types allow NULLs in the database, they must be declared as nullable ints in the model:
// an int can never be null, so it will be created as NOT NULL in db
public int someintfield { get; set; }
// to have a nullable int, you need to declare it as an int?
// or as a System.Nullable
public int? somenullableintfield { get; set; }
public System.Nullable someothernullableintfield { get; set; }