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Yeah, trees in RDBMs can be a PITA. The best way I've seen for handling them is Nested Set Trees, but even that can be a pain if your tree structure gets updated frequently.

Trees is a wellknown problem of SQL

And the "nested set" representation of a tree, explained by Joe Celko, is a well-known solution. Give each node an ID making sure that the IDs' collation is pre-order, and then in each node, store the ID of its first and last descendants. So node B is A's descendant if A.firstdesc <= B.nodeid AND B.nodeid <= A.lastdesc. There are some situations where INSERT statements can become slow (worst case: O(n)), but planning your ID space carefully can ease those.

And Aster nCluster is PostgreSQL based. Yahoo's "homegrown system" also started with PostgreSQL.

According to this article, there are over 70 companies in the Forture 500 listing that are older than the US civil war. The oldest was founded in 1781.

For reference, see The Onion reference, "... We're doing five blades". (Rough language. If you're at a school maybe NSFW). From February, 2004. For the record, the Gillette Fusion with five blades and two lubricating strips was introduced in early 2006.

Hilarious though:

Here's the report from Engineering. Someone put it in the bathroom: I want to wipe my a?? with it. They don't tell me what to invent--I tell them. And I'm telling them to stick two more blades in there. I don't care how. Make the blades so thin they're invisible. Put some on the handle. I don't care if they have to cram the fifth blade in perpendicular to the other four, just do it!

You're taking the "safety" part of "safety razor" too literally, grandma. Cut the strings and soar. Let's hit it. Let's roll. This is our chance to make razor history. Let's dream big. All you have to do is say that five blades can happen, and it will happen. If you aren't on board, then .... you. And if you're on the board, then .... you and your father. Hey, if I'm the only one who'll take risks, I'm sure as hell happy to hog all the glory when the five-blade razor becomes the shaving tool for the U.S. of "this is how we shave now" A.

People said we couldn't go to three. It'll cost a fortune to manufacture, they said. Well, we did it. Now some egghead in a lab is screaming "Five's crazy?" Well, perhaps he'd be more comfortable in the labs at Norelco, working on #### electrics. Rotary blades, my white #!

I'm a big AMD fan but three cores are barely better than two. Buy it anyway - AMD needs to live if the computer market is to be bearable at all in ten years. Via makes some interesting stuff too - and they're not afraid to cut the watts and make them small. You can do some very neat stuff with a low watt CPU on a small board.

It doesn't take a great deal of insight to see we're going to 8 cores per processor on the desktop sometime in the next few years. Dual 16 core processors will happen within ten if competition keeps the pressure up. Personally I don't care if every core is on a separate slab of silicon as long as they integrate in the package well. Yields are better that way I imagine. Somebody tell them to get the watts down. Electricity is mostly made from CO2 emissions:

PCs worldwide consume about 80 billion kilowatt-hours of electricity every year.

And I'm more than a little worried that managers will perceive Joel's article as an endorsement of such yanking.

They had a large property where they just couldn't find gold. They made all of their geology data public and then held a $575k contest for the best suggestions. Using this Open (Gold)Source technique, they found numerous deposits and dramatically increased their market capitalization.

http://www.intelligententerprise.com/showArticle.j html?articleID=159907864

ObjectSpark data components can be deployed on any Microsoft Transaction Server (MTS) or COM+ server. ObjectSpark was originally designed for developers building distributed applications in the Microsoft Windows DNA application framework.

I haven't thought this through, but after reading your post and following through on the path of another post, I came across the following regarding the Rete alogorithm.

The rete algorithm appears to relate to creating a tree structure where each node is a rule and each leaf is a function. So, as the process goes from node to node, and the process evaluates rule after rule, the process comes to the final leaf and calls the desired function.

Celko's books deal with the implementation of trees in databases and he's written some other articles as well.

So, perhaps a person could also handle the rules in the database by a Rete (there's also a Rete 2) algorithm based on nested sets.

www.kx.com,

Celko's article

http://www.intelligententerprise.com/010327/celko_ online.jhtml

read about tick
http://www.kx.com/products/kdb+tick.php

q is used for terabyte datawarehouses on wall street. realtime algorithmic trading.

milan's page.
http://homepage.hispeed.ch/milano/k4kdb+.htm

Would this not constitute evidence that the Office of Homeland Security has adopted Oracle and next up is rolling out Larry Ellison's vision for National ID cards... and with Microsoft rewiring the Navy... the US is setting itself up to fail. Blue Screen Style.

-----------------------
Data in a Time of Terrorism
As America wages war on terrorism, data collection, sharing, and analysis move to the front line

For examples of how use relational architecture for hierarchical data see Trees in SQL by the irrepressable Joe Celko.

Briefly summarized, his approach is: "tree structure can be kept in one table and all the information about a node can be put in a second table."

As for building out a Topical or Hierarchical structure like Yahoo's or DMOZ, you need to have meta data about the document. You can pull meta data from a URL, as was suggested earlier, but I wouldn't advise that. In order for this to work, your URL's start to look like 'http://city.gov/CityCouncil/MinutesOfMeeting/2000 /10/15/index.htm', which also makes it difficult to move things around, and makes it difficult to return the string 'CityCouncil', properly formatted when you build the hierarchy on the fly. If you include the hierarchy information in the page, you can get around some of these problems. I think the standard way to do this would be using meta tags. View the source of this page for an example of this. The downside to this is that you have to structure your hierarchy in advance, which goes back to getting & building requirements early, you also have to convert old documents to include these tags, and you have to make sure that future documents will have these tags properly implemented. If you're using URL paths to qualify the documents, you may be able to take advantage of an already existing directory structure to build your heirarchy. I just don't like using document locations to figure out what a document is about--its always seemed like a brittle solution to me. On the other hand, I've used the URL string to help make a first pass at placing meta tags into documents, usually using a Perl script. I still had to go back in and check the documents though.

I've used both FreeWAIS-SF and Verity for implementing searches like this, as well as home-grown solutions. I wouldn't advise using Verity since I think that it's prohibitively expensive, unless it has some feature that you require and are willing to pay for it. And I didn't think the home-grown solutions worked as well as the off the shelf products that were customized.

I've searched the site for 10 minutes and have not been able to find anything so can someone please provide a link or answer how much it'll cost for a support license for DB that will be used by 20 to 30 employees who will all be accessing it over a local intranet via a web interface?

I am working on my final project for school which involves writing a project management application for a local business and unfortunately all the current RDBMS costs for Windows are in thousands of dollars (Oracle, SQL Server, DB2). We do not plan to support the software after the project is done so a support license is necessary.

PS: I didn't mention mySQL because it isn't an RDBMS. Read the definition of an RDBMS as well as that of a relational database or simply read C.J.Date's reviews of E.F. Codd's seminal 1970 work on relational DBs. Here's part two and part three of C.J. Date's work for anyone who's interested.

I've searched the site for 10 minutes and have not been able to find anything so can someone please provide a link or answer how much it'll cost for a support license for DB that will be used by 20 to 30 employees who will all be accessing it over a local intranet via a web interface?

I am working on my final project for school which involves writing a project management application for a local business and unfortunately all the current RDBMS costs for Windows are in thousands of dollars (Oracle, SQL Server, DB2). We do not plan to support the software after the project is done so a support license is necessary.

PS: I didn't mention mySQL because it isn't an RDBMS. Read the definition of an RDBMS as well as that of a relational database or simply read C.J.Date's reviews of E.F. Codd's seminal 1970 work on relational DBs. Here's part two and part three of C.J. Date's work for anyone who's interested.

I've searched the site for 10 minutes and have not been able to find anything so can someone please provide a link or answer how much it'll cost for a support license for DB that will be used by 20 to 30 employees who will all be accessing it over a local intranet via a web interface?

I am working on my final project for school which involves writing a project management application for a local business and unfortunately all the current RDBMS costs for Windows are in thousands of dollars (Oracle, SQL Server, DB2). We do not plan to support the software after the project is done so a support license is necessary.

PS: I didn't mention mySQL because it isn't an RDBMS. Read the definition of an RDBMS as well as that of a relational database or simply read C.J.Date's reviews of E.F. Codd's seminal 1970 work on relational DBs. Here's part two and part three of C.J. Date's work for anyone who's interested.