Generating dynamic search query for search formular

Question

Hallo guys,
a theoretical question I have there for you.
I have a search form in HTML with several input fields, so the user can search for particular features in a db.
My queiston: How can I generate a dynamic query, depending on which fields the user had filled in?
It should look like this:
> look at the input fields:
> if request.getParameter("art) !=null : Query "+" age
> if request.getParameter("experience") !=0 : Query "+" experience
> if request.getParameter("instrument") != null : Query "+" instrument
> .... and so on
final query = SELECT art, experience,instrument FROM x, y, z WHERE x.art = art AND y.experience > experience AND z.instrument LIKE '%instrumen%' ;I hope I have explained it somehow understandable.
Any help is deeply appreciated! Thank you in advance...
fankoff
Edited by: fankoff on Jun 21, 2010 9:55 AM

Answer 1

for every ? in your preparedQuery, you need a preparedQuery.set...
why do you use reflection to get the length of an array? why not use:
int[] ar = {1,2,3,4};
System.out.println(ar.length);you might want to consider using "... WHERE title IN (title1, title2, ..) OR content IN (content1, content2,...)"
now unfortunatly jdbc seems to be not properly specified with the #setArray, oracle uses it in above mentioned context(e.g. "... WHERE title IN ?" and you set a string-array) mysql doesn't.(you would need something like "...WHERE title IN (?,?,?,?,?)"
but in either of this case, or yours, its usually better to create a prepared query once, and than just insert the values with each fetch. just use enough ?'s and set the not-needed ones to NULL. it will still be more efficient than creating a query everytime.