From: Martijn Tonies
Date: October 19 2004 11:41am
Subject: Re: Ask for help on a mysql problem
List-Archive: http://lists.mysql.com/mysql/174452
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Egor, others,

> It's really clear what you want. Please specify.
>
> If what you basicaly want is just a tree structure, then it's done like
that:
>
>
> CREATE TABLE something (
> id INT AUTO_INCREMENT PRIMARY KEY NOT NULL,
> parent INT NOT NULL,
> data1 CHAR(255),
> data2 CHAR(255),
> ...
>
> );
>
> Then you can specify the parent node id for each record in database.
> This is how tree-like structures are stored in SQL. Hope that helps.

That is ONE way to store a tree structure :-)

Another would be:

ITEMS
(ItemID INT AUTO_INCREMENT PRIMARY KEY NOT NULL,
other stuff)

ITEM_PARENT
(ItemID int,
 ParentID int
primary key (ItemID, ParentID)
)


I prefer the latter.

With regards,

Martijn Tonies
Database Workbench - developer tool for InterBase, Firebird, MySQL & MS SQL
Server.
Upscene Productions
http://www.upscene.com