Dynamically displaying a new region (row?) based on immediate user input

Question

Whew, figuring out a title was almost as hard as trying to explain what I want to do!
Okay, a little background first.
My app has 178 main data fields, spread across about 35 tables. The users want to be able to search any and all data fields. So, I wrote a PL/SQL package that for each master record, loops through all of the child tables and creates (more or less) an XML file for each master record (which I store in a CLOB field). When any data in any table is changed, a trigger fires to re-update that CLOB field as well. I then used Oracle Text to create an index on the CLOB field, and now the users can search across all of the available information for each master record and get a list of which records contained what they were looking for.
So here's the first part of the problem. The app is a Mineral Occurence database for all mineral information world-wide. Say they enter "Brazil" as what they want to search for, they not only retreive all of the mineral sites in Brazil, but also all of the sites where one of the mining companies may be based in Brazil, or Brazil is one of the comments, etc. While this is the expected behaviour, it's still not quite what they expected (but they also don't want to get rid of this behaviour either).
So, since the CLOB field is already formatted with XML-type tags, what I want to do is to have an Advanced Search page, where the user can specify the table name to search, or the field name, or both. What I'd like to do is at the end of each line, have a select list with an "AND" or "OR' box, and if that gets a value, then dynamically create another 'row' underneath the first row, with the same three 'boxes' (actually select lists), and continue on until the user has specified exactly what they want to search for.
I would rather not have to create a whole bunch of regions or rows, and then determine at runtime whether or not to display them.
So i would have (using underscores as the boxes/fields):
Table to Search        Field to Search          And/Or
______________          _____________          _______Each of the above would be a select list.
Anybody have ideas on how I can accomplish this? Any Javascript or AJAX-type solutions that a dummy like me can easily implement? I've seen something almost similar on Carl's example pages to Hide/Show a region(?), but understanding the underlying code and then modifying it for what I want to do is extremely complicated (for me) at best.
Thanks.
Bill Ferguson

Answer 1

Well, after searching through the QBE results (even some of mine), the only thing that comes close is Earl's (http://htmldb.oracle.com/pls/otn/f?p=36337:14). Actually his layout is almost perfect and pretty identical to what I want/need. Vikas' example seems like what I've toyed with on some other pages in my app, using a simple UNION ALL with nulled fields in the select statement, which won't work for what I need, at least I can't seem to visualize how I could incorporate that same code logic.
However, unlike Earl's, when/if the last column (which I'd have as the 'AND/OR' select list) is populated, I'd like to dynamically display another new row.
Now I know I could do it by making the last column a 'Select List With Submit', but that would neccessitate my creating about 25 regions (to hopefully cover the max any of the users would ever need), and then conditionally display the region based on whether or not the previous 'AND/OR' condition field was populated. It would also require a whole slew of page refreshes, which is clunky.
It seems like there should probably be a way with AJAX to accomplish something similar. I think I remember seeing something along these lines in the last year or so on here, but I can't find it.
Something like a cross-breed of Earl's example page above mixed with Carl's example at http://htmldb.oracle.com/pls/otn/f?p=11933:39:4740898821262791902::NO:RP:: which would automatically fire on the poplulation of the last select list is probably the best I can accomplish, unless somebody has some better ideas on how to do this. Using Carl's htmldb_remix code, I can avoid all the submits and the resulting page refreshes, but the code itself will take an old dummy like me a while to figure out.
Thanks for the ideas though.
Bill Ferguson