Fwd: refining view using temp tables

Using postgre with dotnet VS8.  I came up with a scheme of having a web user
search thru the database and selecting into a temp table.  Then a further
"refined" search would use the temp table as input and another temp table as
output.  Then swap the source and destination so as to not use up resources.
Maybe this is not a good mechanism.  I found right away I could not easily
check for table existence nor drop non-existent tables without getting a
server error (even with try {} catch {}).

I may have the same user bring up two or more pages during the same session.
Ditto for other users.  I would not want to code up temporary names using
timestamps and usersnames if I could avoid it.  It would be nice if the sql
engine would handle this for me.   Can someone suggest how postgresql could
handle a google like "search within results".

 

The best approach will probably vary depending on the volume of usage on your site.

One thing I would try is to create a table for searches and search results with a primary key equal to the user's session ID or log in ID.  This would only give them one search but if you need more you can use a serogate key.  Then have everyone use the same table - no temp tables needed.

Table:
user_search
    user_search_id (PK),
    session_id (indexed),
    create_dt,
    last_access_dt

user_search_param (one record for each search parameter they entered for the filter)
    user_search_param_id (PK),
    user_search_id (FK),
    param_name,
    param_value

user_search_results (one record per record returned in search)
    user_search_results_id (PK - this may not be necessary),
    user_search_id (FK),
    sort_index (to help preserve sort order),
    values (this can be CSV, XML or even broken into another table)

Then you can add a process that regularly deletes searches who's last access date is older than so many minutes (cascade delete that is).  Or you can add a trigger that fires off this clean up whenever a new search is added.