Most efficient method of self referencing tree using Entity Framework

Question

So I have a SQL table which is basically

ID, ParentID, MenuName, [Lineage, Depth]

The last two columns are auto-computed to help with sear

Answer 1

I've already spent a while trying to fix a bug in your solution. The stored procedure really don't generate children, grandchildren, etc. Below you will find fixed stored procedure:

CREATE PROCEDURE dbo.UpdateHierarchy AS
BEGIN
  DECLARE @sql nvarchar(MAX)

  SET @sql = ''
  SET @sql = @sql + 'WITH Hierachy(ChildId, ParentId) AS ( '
  SET @sql = @sql + 'SELECT t.Id, t.ParentId FROM dbo.Tree t '
  SET @sql = @sql + 'UNION ALL '
  SET @sql = @sql + 'SELECT h.ChildId, t.ParentId FROM dbo.Tree t '
  SET @sql = @sql + 'INNER JOIN Hierachy h ON t.Id = h.ParentId) '
  SET @sql = @sql + 'INSERT INTO dbo.TreeHierarchy (ChildId, ParentId) ( '
  SET @sql = @sql + 'SELECT DISTINCT ChildId, ParentId FROM Hierachy WHERE ParentId IS NOT NULL '
  SET @sql = @sql + 'EXCEPT SELECT t.ChildId, t.ParentId FROM dbo.TreeHierarchy t '
  SET @sql = @sql + ') '

  EXECUTE (@sql)
END

Mistake: wrong reference. Translating @hazzik code it was:

  SET @sql = @sql + 'SELECT t.ChildId, t.ParentId FROM dbo.Tree t '

but should be

  SET @sql = @sql + 'SELECT h.ChildId, t.ParentId FROM dbo.Tree t '

also I've added code that allows you to update TreeHierarchy table not only when you will populate it.

  SET @sql = @sql + 'EXCEPT SELECT t.ChildId, t.ParentId FROM dbo.TreeHierarchy t '

And the magic. This procedure or rather TreeHierarchy allows you to load Children just by including Ancestors (not Children and not Descendants).

 using (var context = new YourDbContext())
 {
      rootNode = context.Tree
           .Include(x => x.Ancestors)
           .SingleOrDefault(x => x.Id == id);
 } 

Now the YourDbContext will return a rootNode with loaded children, children of rootName's children (grandchildren), and so on.