Searching and Trees

Traversing a tree

Type:	code fragment
Added by:	phpfarm
Entered:	24/05/2001
Last modified:	05/12/2000
Rating:	(3 votes)
Views:	11403

I needed a way of organizing information in a mySQL db. I decided that I would have a column called "parent" which would have in it the ID number of the "parent" of this entry. Meaning that if the ID of "table" were 1, then the parent of "leg" would be set to 1. At the time I did not know it, but this is called a tree. Now I needed to be able to fetch the information OUT of the database. I wanted it to show in a select box, parent[indent]child etc....

so, with MUCH help of Michal Baumann of Maryland/Florida, I (she) wrote this (be sure to change it around as much as your heart/program desires/needs):

<?php
// un tree so to speak this data tree
 function untree($parent, $level)

                            {
 $parentsql = mysql_query("select id, domain from domains where underid=$parent order by domain");
 // if it is a leaf (no data underneath it) then return

                                if (!mysql_num_rows($parentsql))

                                {

                                return;

                                }
 //else echo the result, and recurse the function (so to speak)

                                else

                                {

                                    while($branch = mysql_fetch_row($parentsql))

                                        {

                                        $echo_this = "<option value=$branch[0]>";
 //give it some indents in the select box

                                            for ($x=1; $x<=$level; $x++)

                                            {

                                            $echo_this .=  "&nbsp;&nbsp;&nbsp;";

                                            }

                            

                                        $echo_this.="$branch[1]</option>";
 //echo the <option> tag

                                        echo $echo_this;
 //now run this function and find everthing where the parent is equal to the ID of this entry


                                        $rename_level = $level;

                                        untree($branch[0], ++$rename_level);

                                        }

                                    }

                                }

                            

                            
 /* AND HERE IS HOW YOU CALL THE FUNCTION */

                            

                            // get ALL the entries that have NO parent
 $compsql = mysql_query("select * from domains where underid=0 order by domain");

                                while ($companys = mysql_fetch_array($compsql))

                                {

                                echo "<option value=$companys[id]>$companys[domain]</option>";
 //call the untree function and find all the entries that hive THIS entry as a parent (therefore those entries are children of this one)


                                untree($companys[id], 1);

                                }
?>

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