I've been doing the same recently.
These might be of interest is you find the recursive approach a little
sluggish...
http://www.dbmsmag.com/9604d06.html
http://www.dbmsmag.com/9603d06.html
They are about something called the "preorder tree-traversal algorithm".
Which I think is a nice alternative if a little bit of a mind f**k compared
to the parent/child way.
I did have links to easier to read articles but I can't seem to find them.
Or there is this method...
http://www.planet-source-code.com/vb/scripts/ShowCode.asp?txtCodeId=7321&lng
WId=4
As for displaying the menu, why not try and break it down into smaller bits.
Write a function that displays/or returns the ids that need to be diplayed,
for a given item id. For an id of 0, all the children of 0 are returned. [A]
Write another function that looks up an items parent. [B]
Then maybe create an array that holds the menu item ids that need to be
opened. It will always contain 0, to show the top level items. You could
populate this array by doing a lookup using [B]. Then as [A] goes through
all the items it needs to you can check if the id is in the array and call
the function[A] again with that id as the argument.
If all this seems like it is running slowly, pull back all the data and use
QofQ for all the recursive/parent lookups.
What do you reckon? I hope that made sense.
Ade
-----Original Message-----
From: Dave Phipps [mailto:[EMAIL PROTECTED]
Sent: 17 July 2003 10:29
To: ColdFusion User group
Subject: [ cf-dev ] Selective recurse - help!!
Hi,
I am using a recursive tag to generate some navigation links. The table
structure for the menus is set up in a parent/child relationship with menus
have a parentmenuid equal to the parent menuid or 0 if it is a parent. The
recursive tag grabs the menu then checks for children then calls itself to
check if each child has any children etc.
We have one section of the site with a large number of menus and it looks
pretty ugly. What I want to do is only show the children of the select
parent.
The url to view is:
http://new.abingdon.org.uk/index.cfm?fuseaction=academic.content&cmid=72
The site is not yet live but needs to be sorted asap.
What I want to happen with the menu: When you arrive to the Academic
section you should just see the top level menus (parents) then clicking on
Departments will move to another page with the departments listed. When a
specific department is clicked then the children of this department will be
seen.
If anyone could spare a few moments to take a look and see if there is a
way to alter the tag to do the above that would be great. Is there a
better way to do this navigation?
The code for the tag is below:
<cfsilent>
<cfparam name="theid" default="0">
<cfparam name="mode" default="outline">
<cfparam name="indent" default="0">
<cfparam name="attributes.circuitname" default="">
<cfif IsDefined("attributes.indent")>
<cfset indent = attributes.indent>
</cfif>
<cfif IsDefined("attributes.theid")>
<cfset theID = attributes.theid>
</cfif>
<cfif IsDefined("attributes.mode")>
<cfset mode = attributes.mode>
</cfif>
<cfparam name="attributes.showAll" default="false">
<cfquery datasource="#request.dsn#" name="getMenus" dbtype="ODBC">
SELECT circuits.circuitname, menus.menuid, menus.circuitid,
menus.menuname, menus.parentmenuid, menus.displayorder, contentManager.cmid
FROM circuits, menus, contentManager, content
WHERE parentmenuid = #theid#
AND content.onMenu = 1
<cfif attributes.showAll EQ false>AND content.isApproved = 1</cfif>
AND contentManager.contentid = content.contentid
AND contentManager.menuid = menus.menuid
AND circuits.circuitid = menus.circuitid
AND circuits.circuitname = '#attributes.circuitname#'
ORDER BY menus.displayorder, menuid, parentmenuid
</cfquery>
</cfsilent>
<cfloop query="getMenus">
<cfset thisid = getMenus.cmid>
<cfoutput>
<span class="navbar" style="margin-left:#indent#px;">
<cfif attributes.cmid EQ thisid OR
(IsDefined("caller.getFirstPage.recordcount") AND caller.getFirstPage.cmid
EQ thisid)>
<img src="images/site_gfx/arrow_blue.gif"
border="0"
name="section#menuid#"><span style="color:##7C8AA2;">#menuname#</span>
<cfelse>
<a
href="#request.self#?fuseaction=#getMenus.circuitname#.content&cmid=#cmid#"
onMouseOut="MM_swapImgRestore(); self.status=''; return true;"
onMouseOver="MM_swapImage('section#menuid#','','images/site_gfx/arrow_red.gi
f',1);
self.status='#Replace(menuname, "'", "", "ALL")#'; return true;"><img
src="images/site_gfx/arrow_black.gif" border="0"
name="section#menuid#">#menuname#</a>
</cfif>
</span><br>
</cfoutput>
<cfquery datasource="#request.dsn#"
cachedwithin="#CreateTimeSpan(0,0,0,2)#" name="checkForChild" dbtype="ODBC">
SELECT menuid
FROM menus
WHERE parentmenuid = #getMenus.menuid#
</cfquery>
<cfif checkForChild.RecordCount gt 0>
<cfset nextindent = indent + 10>
<cfif attributes.showAll EQ true>
<cfset attributes.showAll = true>
</cfif>
<cf_buildtree theid = "#getMenus.menuid#" mode = "#mode#"
indent="#nextindent#" circuitname="#attributes.circuitname#"
cmid="#attributes.cmid#" showAll="#attributes.showAll#">
</cfif>
</cfloop>
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