NYCPHP Meetup

[Roland Cozzolino]

Just curious, it this something that needs to be saved to the database 
(sort of like saved queries a user can bring back)?  If not, you can do 
this with sessions.  I am actually implementing something very similar 
right now with open ended queries where we simply give the user a 
buttload of fields to choose from including boolean options.  Since I 
don't care about the query once it returns a result, I assemble it on 
the fly and use DOM/DHTML and a bit of ajax to deal with the 
addition/subtraction of query fields.  Not sure if this helps.

Allen Shaw wrote:

>All this heirarchical structure talk happens to come up as I'm trying to 
>implement a data filtering scheme for an ad-hoc querying interface.  
>Basically I want to allow queries as complex as the user wants -- not 
>just on one or two fields at a time -- so this has to be open-ended, and 
>it seems to be pointing me to a heirarchical structure.  I think I've 
>found something that will work, but I wonder a) if I'm just reinventing 
>the wheel somehow, and b) if I should go with this, am I doing it right?
>
>Here goes (in English as simple as my gabby self can make it):
>
>We store all the filters using a table with these fields:
>CREATE TABLE `filters` (
>  `filterid` int(11),
>  `parentid` int(11), -- keys to filterid
>  `booltype` enum('and','or'),
>  `criteria` varchar(255),
>  PRIMARY KEY  (`filterid`)
>);
>And then we start filling it with filters. Any 'parent' filter doesn't 
>store a `criteria` for itself, just the `booltype` value for all its 
>children.
>
>INSERT INTO `filters` (`filterid`, `parentid`, `booltype`, `criteria`) 
>VALUES (1, NULL, 'and', NULL);
>INSERT INTO `filters` (`filterid`, `parentid`, `booltype`, `criteria`) 
>VALUES (2, 1, NULL, 'hair=''brown''');
>INSERT INTO `filters` (`filterid`, `parentid`, `booltype`, `criteria`) 
>VALUES (3, 1, NULL, 'age=''32''');
>INSERT INTO `filters` (`filterid`, `parentid`, `booltype`, `criteria`) 
>VALUES (4, 1, 'or', NULL);
>INSERT INTO `filters` (`filterid`, `parentid`, `booltype`, `criteria`) 
>VALUES (5, 4, NULL, 'city=''boston''');
>INSERT INTO `filters` (`filterid`, `parentid`, `booltype`, `criteria`) 
>VALUES (6, 4, NULL, 'city=''houston''');
>
>So this way I get parent filter 1 joining its children 2, 3 and 4 with 
>an 'and' operator; 4 itself also is a parent of 5 and 6, which it joins 
>with an 'or' operator.  The result is a filter that says:    hair = 
>'brown' and age='32' and (city='boston' or city='houston')
>
>This seems open-ended enough to be very flexible, and it makes sense to 
>my feeble brain, but is there a better way to do it?
>
>- Allen
>
>  
>