I need some quality sources - books, websites etc. - to educate myself about putting multiple hierarchy trees in a single table using SQL.

I'm looking for some good theoretical and practical information.

  • See: Models for Hierarchical Data It's MySQL biased but it has basic discussion about the various models and code. – ypercubeᵀᴹ Sep 22 '12 at 18:35
  • Can you elaborate on what you mean by "multiple" hierarchy trees? – Michael - sqlbot Sep 22 '12 at 22:01
  • I know I can put everthing in one tree and use different entry points but I think depending on how I store the data there is possibly a lot of additional data depending on how wide or deep the tree gets. – Wozilla Sep 22 '12 at 23:18
  • -1 since your question is not clear. If you add some sample data, perhaps your question would be clearer. – Hannah Vernon Sep 25 '12 at 18:40
  • I wouldn't be able to explain everything very specifically at this point, and even more vague information wouldn't make things better. ypercube's comment was actually very helpfull. and thank you for the edit. – Wozilla Sep 25 '12 at 21:11

You can put multiple hierarchies in an Oracle table and query it using a hierarchical query. See the documentation.


What we have done with LedgerSMB for our business reporting dimensions (each dimension is hierarchical) is to have a dimensions table, and a units table. Each member of the units belongs to a dimension, and we define hierarchy using the self join of (parent, unit_class) references (id, unit_class). This way we have multiple equivalent hierarchies sharing a table.

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