[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: Why Multipath (LCA) Hierarchical Query Processing Works A
Peter, Don't suppose you can post your schema and some examples of how you use it? It sounds very interesting. best, -Rob On Aug 3, 2009, at 8:58 AM, Peter Hunsberger wrote: > On Sun, Aug 2, 2009 at 11:41 PM, <mike@adatinc.com> wrote: >> Joe Celko's and the other hierarchical processing solutions you >> mentioned is >> to use external programmable hierarchical programming functions and >> they >> also do not handle the necessary multiple node type and multiple data >> occurences necessary for XML. > > Not sure what you mean by "external programmable hierarchical > programming functions" You can use set/subset hierarchies with pure > SQL. Nothing external is required....? > > They can certainly handle multiple node types and multiple data > occurrences: just map the hierarchy using a table that is pure set / > subset and use a foreign key from it to a table joining multiple types > and / or multiple occurences as needed. > >> Using the Left Out Join in a hierarhical data >> modeling fashion allows full multipath hierarchical processing to be >> transparently performed automatically and correctly including >> nonlinear >> multipath queries. See my DevX ANSI SQL Hierarchical Processing >> article at: >> http://www.devx.com/xml/Article/39183/1954 >> > > I read your articles, frankly I don't get it. Like I said, I can't see > how to manage large tree structures in the way you suggest. In one > application we manage about 200 different major tree structures, one > instance of these has 60,000+ main nodes in it. These nodes represent > in the order of 50 major types and probably over 200 subtypes. The > tree nodes point to in the order of 300,000 data instances (this > particular tree is relatively sparsely populated). All this is managed > with about 10 tables using set / subset. Any path traversal that I > need for any use case I've ever seen is realizable in pure ANSI SQL. > We create XML from these tables, on demand to build navigation menus, > OWL ontology dumps, and data management screens (which may include > multiple levels of hierarchy depending on the use case). > > What am I missing here? > > -- > Peter Hunsberger > > _______________________________________________________________________ > > XML-DEV is a publicly archived, unmoderated list hosted by OASIS > to support XML implementation and development. To minimize > spam in the archives, you must subscribe before posting. > > [Un]Subscribe/change address: http://www.oasis-open.org/mlmanage/ > Or unsubscribe: xml-dev-unsubscribe@lists.xml.org > subscribe: xml-dev-subscribe@lists.xml.org > List archive: http://lists.xml.org/archives/xml-dev/ > List Guidelines: http://www.oasis-open.org/maillists/guidelines.php >
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