Menus and menu items

In cms I have Categories (hierarchy), Pages (hierarchy) and Links (any other link, like specific search link or link to external site). I want to introduce Menus and allow users to modify them (to change menu items). Menu item should be some Category, Page or Link. So, I need to link table Menus with three different tables that contain menu items. What is the best solution to this?


Categories (id, parent_id, name, ...)
	Used cars -> Ford		( /used-cars/ford )
	Used cars -> Ford -> Fiesta	( /used-cars/ford/fiesta )
	Used cars -> Mazda		( /used-cars/mazda )
	...

Pages (id, parent_id, name, path, ...)
	Home			( / )
	About us		( /about-us )
	About us -> Strategy	( /about-us/strategy )
	About us -> History	( /about-us/history )
	Contact			( /contact )
	Finance			( /finance )
	Advanced search		( /search )
	...
	
Links (id, name, url, ...)
	Diesel cars		( /used-cars/q/fuel/diesel )
	Hatchbacks		( /used-cars/q/style/hatchback )
	Loans			( http://www.loan-partner-site.com )
	...

Menus (id, name, desc, ...)
	Main menu
	Left menu
	Search menu


Main menu
------------
Home		( page )
About us	( page )
Contact		( page )
...

Left menu
------------
Used cars	( category )
Finance		( page )
Loans		( link )
...

Search menu
------------
Ford cars		( category )
Mazda cars		( category )
Diesel cars		( link )
Hatchbacks		( link )
Advanced search		( page )
...