Special

Introducing the “Welcome to Xojo” Bundle!

New to Xojo and looking for guidance? We've put together a terrific bundle to welcome you! Xojo Bundle

This bundle includes six back issues of the magazine -- all of year 14 in printed book and digital formats -- plus a one-year subscription so you'll be learning all about Xojo for the next year. It's the perfect way to get started programming with Xojo. And you save as much as $35 over the non-bundle price!

This offer is only available for a limited time as supplies are limited, so hurry today and order this special bundle before the offer goes away!

Article Preview


Buy Now

Issue 11.6 ('Apple About Boxes')
Instant purchase and download via GumRoad!

COLUMN

Hierarchies Using The Path Enumeration Model

Hierarchies Part Two

Issue: 11.6 (November/December 2013)
Author: Craig Boyd
Author Bio: Craig Boyd is currently an Oracle DBA for a well-known national retailer. But in his 18 years of IT experience, he has been everything from a PC Technician to iSeries System Administrator to iSeries Programmer, a Sr. Technical Lead and a Data Modeler. He lives in the great state of Texas with his wife and two kids.
Article Description: No description available.
Article Length (in bytes): 7,017
Starting Page Number: 67
Article Number: 11613
Related Link(s): None

Excerpt of article text...

In the last column we spoke about hierarchies and one approach for handling them: the adjacency model. By way of review the adjacency model stores the parent records value in the child's row. So you are always connected to one parent and it is the most immediate parent. For this issue's column we are going to continue our discussion of hierarchies, but we are going to talk about a different approach. This second approach to storing hierarchies in a database is called the path enumeration model. With the path enumeration model, rather than having the parent's id as part of the child record, you have the full path stored in a column. Here is the hierarchy we used last time:

Employee Manager

Joe {NULL}

Frank Joe

Susan Joe

...End of Excerpt. Please purchase the magazine to read the full article.


Home | Store | Browse Published Issues | Customer Service | Contribute | xDevLibrary

Site Copyright 2002-2017 by xDev Magazine and DesignWrite.
Xojo is a trademark of Xojo, Inc..