Re: BOOLEAN RELATIONSHIPS: HARD QUESTION

From: --CELKO-- <jcelko212_at_earthlink.net>
Date: 14 Jun 2004 19:16:56 -0700
Message-ID: <18c7b3c2.0406141816.8947481_at_posting.google.com>

>> We build machines and so we have a part list of the components. I
have created a model of the machine in which there is a list of components to be filled in order to complete the design scheme. Every machine will be composed by:

 1 mandatory element of type "A" among the entire list of A type items
 1 mandatory element of type "B" among the entire list of B type items
 4 mandatory element of type "C" among the entire list of C type items

 N optional element of type "D" among the entire list of D type items  

 The problem is this. When you choose a specific element to fill the type "A"
 box you can't then choose among all the items of list B to fill the type B
 box but among those B elements that matches the selected A items. <<

Here is the link on Amazon.com for my new book on "Trees & Hierarchies in SQL"

http://www.amazon.com/exec/obidos/tg/detail/-/1558609202/qid=1080772873/sr=1-1/ref=sr_1_1/102-7683601-6345721?v=glance&s=books#product-details

You can make "the machine" the root, the second level is the "A" parts (with one child); the third level is the "B" parts (with 4 children); etc. The valid configurations are paths in the tree from the root to leaf nodes. Look up the nested set model. Received on Tue Jun 15 2004 - 04:16:56 CEST