Add this attribute to your data interface to control the physical store sort order of data. This concept is known as the clustered index on SQL Server.

public sealed class StoreSortOrderAttribute : Attribute

Public NotInheritable Class StoreSortOrderAttribute _
	Inherits Attribute

public ref class StoreSortOrderAttribute sealed : public Attribute

[StoreSortOrderAttribute("Date", "Title")]
// (other IData attributes)
interface IMyDataType : IData
{
    // data type properties, must include Date and Title since we ref them above
}