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Table Hierarchy updated

Recently a need resurfaced to explore the foreign key tree (hierarchy/genealogy) as it related to a specific table within a database.  As I pulled out the script from the repository, I realized there was some unfinished work to be done.  But there was also some polish that needed to be added.  This is an update to the most recent posting of that script.  You can see several revisions in the series at this link or the group here.

Some of the changes involve formatting and and labeling.  I added a new column called “Direction” to help understand the relationship of the key to the table in question.  I also changed up the FKGenealogy (formerly called SortCol) to reflect the source table more accurately in the case when the key comes from an ancestor rather than a descendant.  The Level of the FK was also modified to help understand a little better how far away the ancestor was in relationship to the origin table.

A final adjustment also comes from the Genealogy attribute.  Ancestors were all starting at the wrong point in the lineage.  I adjusted that so the lineage can be seen from the point in the tree that the ancestor is related rather than as a root direct from the origin table.

All in all, this script should make more sense to the user than the previous versions.

DECLARE    @StartParentTable    VARCHAR(256);
 
SELECT @StartParentTable = 'tblCampaignMain';
 
WITH Posterity (ParentTable,ParentColumn, ChildTable,ChildColumn, FKLevel, FKGenealogy) AS (
  SELECT OBJECT_NAME(sfk.referenced_object_id) AS ParentTable
          ,COL_NAME(sfkc.referenced_object_id,sfkc.referenced_column_id) AS ParentColumn
          ,OBJECT_NAME(sfk.Parent_object_id) AS ChildTable
          ,COL_NAME(sfkc.parent_object_id,sfkc.parent_column_id) AS ChildColumn
          ,0 AS FKLevel
          ,CAST('.'+CAST(OBJECT_NAME(sfk.referenced_object_id) AS VARCHAR(MAX))+'.' AS VARCHAR(MAX))
      FROM sys.foreign_key_columns sfkc
          INNER Join sys.foreign_keys sfk
              ON sfkc.constraint_object_id = sfk.OBJECT_ID
      WHERE OBJECT_NAME(sfk.referenced_object_id) = @StartParentTable
  UNION All
  SELECT OBJECT_NAME(sfk.referenced_object_id) AS ParentTable
          ,COL_NAME(sfkc.referenced_object_id,sfkc.referenced_column_id) AS ParentColumn
          ,OBJECT_NAME(sfk.Parent_object_id) AS ChildTable
          ,COL_NAME(sfkc.parent_object_id,sfkc.parent_column_id) AS ChildColumn
          ,FKLevel + 1
          ,STUFF(('.' + F.FKGenealogy + CAST(CAST(OBJECT_NAME(sfk.referenced_object_id) AS VARCHAR(MAX)) + '.' AS VARCHAR(MAX))
                      ),1,1,'')
      FROM sys.foreign_keys sfk
          INNER Join Posterity F
              ON OBJECT_NAME(sfk.referenced_object_id) = F.ChildTable
              And F.FKGenealogy NOT LIKE '%'+CAST(OBJECT_NAME(sfk.referenced_object_id) AS VARCHAR(MAX))+'%'
          INNER Join sys.foreign_key_columns sfkc
              ON sfkc.constraint_object_id = sfk.OBJECT_ID
      WHERE OBJECT_NAME(sfk.referenced_object_id) <> @StartParentTable
          And sfk.referenced_object_id <> sfk.parent_object_id
), Ancestry (ParentTable,ParentColumn, ChildTable,ChildColumn, FKLevel, FKGenealogy) AS (
  SELECT DISTINCT OBJECT_NAME(sfk.referenced_object_id) AS ParentTable
      ,COL_NAME(sfkc.referenced_object_id,sfkc.referenced_column_id) AS ParentColumn
      ,OBJECT_NAME(sfk.Parent_object_id) AS ChildTable
      ,COL_NAME(sfkc.parent_object_id,sfkc.parent_column_id) AS ChildColumn
      ,(FKLevel * -1)-1 AS FKLevel
      ,F.FKGenealogy + CAST(CAST(OBJECT_NAME(sfk.Parent_object_id) AS VARCHAR(MAX))+'.' AS VARCHAR(MAX))
  FROM Posterity F
      INNER Join sys.foreign_keys sfk
          ON F.ChildTable = OBJECT_NAME(sfk.parent_object_id)
          And F.ParentTable <> OBJECT_NAME(sfk.referenced_object_id)
      INNER Join sys.foreign_key_columns sfkc
          ON sfkc.constraint_object_id = sfk.OBJECT_ID
  UNION All
  SELECT OBJECT_NAME(sfk.referenced_object_id) AS ParentTable
      ,COL_NAME(sfkc.referenced_object_id,sfkc.referenced_column_id) AS ParentColumn
      ,OBJECT_NAME(sfk.Parent_object_id) AS ChildTable
      ,COL_NAME(sfkc.parent_object_id,sfkc.parent_column_id) AS ChildColumn
      ,F.FKLevel -1
      ,STUFF(('.' + FKGenealogy + CAST(CAST(OBJECT_NAME(sfk.referenced_object_id) AS VARCHAR(MAX)) + '.' AS VARCHAR(MAX))
                  ),1,1,'')
  FROM Ancestry F
      INNER Join sys.foreign_keys sfk
          ON F.ParentTable = OBJECT_NAME(sfk.parent_object_id)
      INNER Join sys.foreign_key_columns sfkc
          ON sfkc.constraint_object_id = sfk.OBJECT_ID
  WHERE F.ParentTable not in (SELECT ParentTable FROM Posterity)
      And sfk.referenced_object_id <> sfk.parent_object_id
      And F.ChildTable not IN (SELECT ChildTable FROM Posterity)
)
 
SELECT ParentTable,ParentColumn, ChildTable,ChildColumn, FKLevel, FKGenealogy
	,CASE 
		WHEN FKLevel > 0 THEN 'Descendant' 
		WHEN FKLevel = 0 THEN 'Root'
		END AS Direction
FROM Posterity
UNION All
SELECT ParentTable,ParentColumn, ChildTable,ChildColumn, FKLevel, FKGenealogy
	,'Ancestor' AS Direction
FROM Ancestry
  ORDER BY FKGenealogy ASC, Direction DESC
  OPTION (maxrecursion 500);

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