NYCPHP Meetup

[Peter Sawczynec]

You should further study the topic: 'database normalization' to get more
grasp of 
how to handle table relationships as the industry has generally settled on. 

The following type of three table structure should offer solution to your
issue. 
Roughly creating as follows should get you started. 

"Employee" table fields:
ID 
Employee_ID
First_Name 
Last_Name
Address

"Employee_Attrributes" table fields:
ID 
Employee_ID 
Category_ID

"Available_Categories" table fields:
ID
Category_Name


"Employee" table and "Employee_Attributes" tables have an infinitely
expandable, one to many, primary key to foreign key relationship.

Save a new row entry into "Employee_Attributes" table every time an Employee
is added to a new category. 
Then perform multi-table SELECT queries using JOIN, LEFT JOIN, or RIGHT JOIN
when you need to get the Employee category info.

That should tide you over.

Warmest regards,
 
Peter Sawczynec,
Technology Director
PSWebcode
_Design & Interface
_Ecommerce
_Database Management
ps at pswebcode.com
646.316.3678
www.pswebcode.com
 



-----Original Message-----
From: talk-bounces at lists.nyphp.org [mailto:talk-bounces at lists.nyphp.org] On
Behalf Of LK
Sent: Friday, September 08, 2006 10:35 AM
To: talk at lists.nyphp.org
Subject: Re: [nycphp-talk] PHP and MySQL projects to include in a portfolio.


Neil,

I happen to be struggling now with a database issue that might interest you
and I'd welcome and appreciate suggestions from the group.

My issue is: With a relational database how do you represent and navigate a
tree with unlimited number of levels and branches ? Example: categorization
hierarchy. Let's say you have a table of Employees. Now you want to
categorize them by Job_Type: clerk, secretary, manager, etc. But each one of
these can be further sub-categorized, e.g. Manager: production, purchasing,
accounting etc. Each one of those can also be sub-categorized in an
unlimited recursive fashion. 

One could try constructing a table with columns: level_0 level_1 level_2
etc. where level_0 holds the 0-th level categories, level_1 - first level
subcategories, etc. But what if the number of category levels is potentially
unlimited - what do you do then?

Seems like this must have been dealt with before somewhere, and any
suggestions and pointers would be greatly appreciated.

Leo Kokin



--- Neil Argent <neil.argent at gmail.com> wrote:

> Following an absence from work due a long term illness, I have just
> completed the CIW Master Designer qualification to assist me in my to 
> return to work.  
>  
> To facilitate my return, it is apparent that I need to learn PHP and
> demonstrate its use with and without MySQL.
>  
> Could you suggest examples that I should write and use as part of my
> portfolio.
>  
> I am not looking for detailed descriptions, just brief outlines of
> projects that will demonstrate the skills being considered for PHP
> employment at this time.  
>  
> I have some experience of using PHP5 and PHP4 with MySQL, and a lot 
> more
> experience in C++, so I am not coming at it as a complete programming 
> novice.
> 
> Thanks.
> _______________________________________________
> New York PHP Community Talk Mailing List 
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> 
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> 
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> http://www.nyphp.org/show_participation.php
> 


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