A server with multiple choice queries

Serving multiple selections

Selections

When a W3 server offers the user a choice of options, typically it will do this with a hypertext page with pointers to virtual pages whos addresses contain a coded version of the option that the user has selected. (See making a server for existing data )

So, for example the page /calendar may ask "which page do you want?" and have several anchors to point to pages /calendar/monday, calendar tuesday, etc. (see example )

Multiple selections

This can be extended to multiple selections. (See Example case ). In this case, the address fo a document may contain a serious of options separated for example by "plus" signs.

Suppose that in Gary's example , we represent the particle types by short acronymous: 

	> GH	_  GAUGE AND HIGGS BOSONS
	> LU	_  LIGHT UNFLAVORED MESONS
	...
	> BB	_  BOTTOM (BEAUTY) BARYON
	> ET	_  SEARCHES FOR FREE QUARKS, ..., COMPOSITENESS, ETC.
and then suppose that the initial page is called /query. Query itself is not an index because there is not enough information for the search. The user is given a list of choices pointing to nodes named /query/GH etc.

This is a straightforward selection. Once he has selected GH, for example, he can now be given BOTH the option of searching at that poin, and ALSO links to modified searches:

/query/GH+LU
Also search LU. An almost identical will be displayed, but instead of the links to "Also serach LU" there will be one to "Don't search LU", a link back to /query/GH
/query/GH+OL
Also search OL. As above but for LU read OL. And so on.
There ar e19 of these links, which basically allow him to toggle on or off the 19 groups in the list. If 19 is too many, you could route him through a single option "Add/remove groups" called say /query/GH+LU/CHANGE but that would make the selection process slower. With direct links, the result will look very much like pressing radio buttons, in that clicking on an option should immediately present him with a page with that one option toggled.

There are also links to select at the next level down. leading to pages:

/query/GH/Omega
Specify a search for Omega.
/query/GH/Omega2250
Specify a search for Omega(2250). (etc)
Suppose the user follows GH first, then BB and end up in /query/GH+BB. He then follows Omega and then lambda to end up at /query/GH+BB/Omega+Lambda. He still has 19 links to toggle particle classes, 4 links to toggle particles, but he now has also 6 links to select what sort of data he wants returned. he ends up with a node looking like

/query/GH+BB/Omega+Lambda/H+D

Which means that he wants all all header and decay data for the Omega and Lambda particles. That document could be just a menu, with a (prominent) link to the data itself, or it could contain the data itself.

Holding back the data

If your search is fast, then you might want to do it every time. If it is slow, you might want to make sure the user has the query absolutely right, and then follows a link to the actual data. If you can mention how many lines of data he will get, then that might be useful information to include in the link:

Review Results (12367 lines)

will make him pause and save some network traffic! (The link there is dummy).

Line mode and the text input altrenative

It is true that with the line mode browser you have to type in a lot of numbers. To ease that, you could set the ISINDEX flag on your documents, and allow some sort of text to be typed in by users who know the ropes and want to get there fast. You have to pick a syntax which is simple, but just toggling any recognizable keywords in the user input would work OK in this case. It would allow the person to say 
			FIND OMEGA ALL
and immediately get something back. This would allow him to make a command line alias forthe PDG data so that if very command-line oriented he could type 
		alias pdg www http://etce.etc.etc/query

		pdg omega all
which would really appeal to a certain set of people (which includes me!). Keep this low-profile in parallel with the hypertext method. Put a link to the doc on how to use a text search in at least the entry page.
Tim BL