# Re: Mixing OO and DB

From: Bob Badour <bbadour_at_pei.sympatico.ca>

Date: Thu, 13 Mar 2008 12:56:42 -0300

Message-ID: <47d94ebf$0$4057$9a566e8b_at_news.aliant.net>

>>Bob Badour wrote:

Date: Thu, 13 Mar 2008 12:56:42 -0300

Message-ID: <47d94ebf$0$4057$9a566e8b_at_news.aliant.net>

topmind wrote:

> On Mar 12, 9:14 am, S Perryman <q..._at_q.com> wrote: >

>>Bob Badour wrote:

*>>**>>>>Robert Martin wrote:**>>>>**>>>>>That's fine. Consider, for example, an algorithm that finds the**>>>>>minimum spanning distance of a graph. (e.g. cheapest network route, or**>>>>>cheapest travel itinerary, etc). The node and edges of the graph are**>>>>>stored in database tables.**>>>>>Shall we execute that algorithm by doing thousands of tiny queries as**>>>>>we walk from node to node through the edges? Or shall we query all the**>>>>>nodes and edges in one gulp, arrange them into a graph of objects, and**>>>>>walk through them that way?**>>>**>>>If one studies the algorithms for minimum spanning trees, one quickly**>>>sees the task involves no traversals whatsoever. In fact, one generally**>>>creates the MST as a precursor to some sort of traversal, and the**>>>algorithms themselves are specified in terms of sets, which makes them**>>>ideal for implementing relationally.**>>**>>What about the canonical graph algorithms (breadth/depth first, transitive**>>closure etc) ??*What about them? Where exactly did they appear in the algorithm I described for evaluating the minimum spanning forest? How exactly would an MST algorithm using some sort of traversal method deal with a multi-tree forest? How exactly would it traverse from one disjoint tree to another?

[snip] Received on Thu Mar 13 2008 - 16:56:42 CET