Sequential GUID in Linq-to-Sql?

Question

I just read a blog post about NHibernate's ability to create a GUID from the system time (Guid.Comb), thus avoiding a good amount of database fragmentation. You could call it the client-side equivalent to the SQL Server Sequential ID.

Is there a way I could use a similar strategy in my Linq-to-Sql project (by generating the Guid in code)?

Answer 1

C# (safe) code (Compliments of the NHibernate Guid Comb Generator)

Guid GenerateComb()
{
    byte[] destinationArray = Guid.NewGuid().ToByteArray();
    DateTime time = new DateTime(0x76c, 1, 1);
    DateTime now = DateTime.Now;
    TimeSpan span = new TimeSpan(now.Ticks - time.Ticks);
    TimeSpan timeOfDay = now.TimeOfDay;
    byte[] bytes = BitConverter.GetBytes(span.Days);
    byte[] array = BitConverter.GetBytes((long) (timeOfDay.TotalMilliseconds / 3.333333));
    Array.Reverse(bytes);
    Array.Reverse(array);
    Array.Copy(bytes, bytes.Length - 2, destinationArray, destinationArray.Length - 6, 2);
    Array.Copy(array, array.Length - 4, destinationArray, destinationArray.Length - 4, 4);
    return new Guid(destinationArray);
}

A link to the source on github: https://github.com/nhibernate/nhibernate-core/blob/master/src/NHibernate/Id/GuidCombGenerator.cs