Hierarchy Problem -> Replace Recursion with Linq Join?

Question

I have a self referential table, which has ID, ParentID (nullable).

So, the table contains many nodes, each node could be the root in the hierarchy (parent is null),

Answer 1

If you want to select all direct children of a node, a simple query like the following should do the job:

from item in table
where item.ID == parentID;
select item

If you want to select all descendants of a node, this is not possible with LINQ, because it requires recursion or a stack which LINQ (and SQL) doesn't provide.

See also:

• StackOverflow: LINQ to SQL for self-referencing tables?
• CodeProject: T-SQL - How to get all descendants of a given element in a hierarchical table
• StackOverflow: Expressing recursion in LINQ