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    <p>You could use supporting hierarchy table to do eager loading of unlimited levels of tree.</p> <p>So, you need to add two collections <code>Ancestors</code> and <code>Descendants</code>, both collection should be mapped as many-to-many to supporting table. </p> <pre><code>public class Tree { public virtual Tree Parent { get; set; } public virtual ICollection&lt;Tree&gt; Children { get; set; } public virtual ICollection&lt;Tree&gt; Ancestors { get; set; } public virtual ICollection&lt;Tree&gt; Descendants { get; set; } } </code></pre> <p>Ancestors will contain all ancestors (parent, grand-parent, grand-grand-parent, etc.) of the entity and <code>Descendants</code> will contain all the descendants (children, grand-children, grand-grand-children, etc) of the entity.</p> <p>Now you have to map it with EF Code First:</p> <pre><code>public class TreeConfiguration : EntityTypeConfiguration&lt;Tree&gt; { public TreeConfiguration() { HasOptional(x =&gt; x.Parent) .WithMany(x =&gt; x.Children) .Map(m =&gt; m.MapKey("PARENT_ID")); HasMany(x =&gt; x.Children) .WithOptional(x =&gt; x.Parent); HasMany(x =&gt; x.Ancestors) .WithMany(x =&gt; x.Descendants) .Map(m =&gt; m.ToTable("Tree_Hierarchy").MapLeftKey("PARENT_ID").MapRightKey("CHILD_ID")); HasMany(x =&gt; x.Descendants) .WithMany(x =&gt; x.Ancestors) .Map(m =&gt; m.ToTable("Tree_Hierarchy").MapLeftKey("CHILD_ID").MapRightKey("PARENT_ID")); } } </code></pre> <p>Now with this structure you could do eager fetch like following</p> <pre><code>context.Trees.Include(x =&gt; x.Descendants).Where(x =&gt; x.Id == id).SingleOrDefault() </code></pre> <p>This query will load entity with <code>id</code> and all of it descenadnts.</p> <p>You could populate the supporting table with following stored procedure:</p> <pre><code>CREATE PROCEDURE [dbo].[FillHierarchy] (@table_name nvarchar(MAX), @hierarchy_name nvarchar(MAX)) AS BEGIN DECLARE @sql nvarchar(MAX), @id_column_name nvarchar(MAX) SET @id_column_name = '[' + @table_name + '_ID]' SET @table_name = '[' + @table_name + ']' SET @hierarchy_name = '[' + @hierarchy_name + ']' SET @sql = '' SET @sql = @sql + 'WITH Hierachy(CHILD_ID, PARENT_ID) AS ( ' SET @sql = @sql + 'SELECT ' + @id_column_name + ', [PARENT_ID] FROM ' + @table_name + ' e ' SET @sql = @sql + 'UNION ALL ' SET @sql = @sql + 'SELECT e.' + @id_column_name + ', e.[PARENT_ID] FROM ' + @table_name + ' e ' SET @sql = @sql + 'INNER JOIN Hierachy eh ON e.' + @id_column_name + ' = eh.[PARENT_ID]) ' SET @sql = @sql + 'INSERT INTO ' + @hierarchy_name + ' ([CHILD_ID], [PARENT_ID]) ( ' SET @sql = @sql + 'SELECT [CHILD_ID], [PARENT_ID] FROM Hierachy WHERE [PARENT_ID] IS NOT NULL ' SET @sql = @sql + ') ' EXECUTE (@sql) END GO </code></pre> <p>Or even you could map supporting table to a view:</p> <pre><code>CREATE VIEW [Tree_Hierarchy] AS WITH Hierachy (CHILD_ID, PARENT_ID) AS ( SELECT [MySuperTree_ID], [PARENT_ID] FROM [MySuperTree] AS e UNION ALL SELECT e.[MySuperTree_ID], e.[PARENT_ID] FROM [MySuperTree] AS e INNER JOIN Hierachy AS eh ON e.[MySuperTree_ID] = eh.[PARENT_ID] ) SELECT [CHILD_ID], [PARENT_ID] FROM Hierachy WHERE [PARENT_ID] IS NOT NULL GO </code></pre>
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    1. COIs there any acceptable way to achieve this in Model First development? I ended up calling EF using Includes' in a recursive loop to get the entire hierarchy loaded :(
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    2. COI can't get the above solution to work in EF5. My "Descendants" collection only contains my Children, not all nodes beneath me (ie Children, Grand Children, Great-Grand....and so on). My Hierarchy-view is correctly showing the entire tree with parent/child keys, but this isn't reflected in the Descendants collection. Any ideas?
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