Ok, first…does anyone have the source code for altavista? 😉
I’ve been struggling with a logic problem at many client projects.
Lets say, for a web page, a user of the system selects a page that lists all items for sale in our company catalog. Lets assume the list of items is qty 1 million. Lets also assume (while filtering options are available), the user currently is browsing the entire list, rather than shortening the rowset by some pre-defined filter.
Obviously, I would like to present the user with a page (similar to search engines) that allows them to select an option of viewing 25 items per page, and flip through the items page by page, while sorting by a user selected column.
This issues I’ve had are:
1. Since a web page is stateless, how do a select the first 25 records from a database, then the next 25…etc, all based on the choice of sort column. With indexes this is fairly simple, but i hate to index 30 columns in a table, many of which are varchars.
2. ADO Provides this ability, but also grabs the entire recordset. (A Bad thing when pumping data across an n-tier system to a user through a 56k dialup).
3. If a user sits on one of the pages for 25 minutes, and new data is entered by another user during that time, the next page, or subsequent pages should reflect the changes and grab the current recordset.
I’m struggling with the methodology of how to walk through a very large rowset from a web front-end while maintaining uniqueness of the results, keeping the system stateless, and not having to return the entire rowset for each page (only the 25 records viewed for that page, rather than the 1 million available records).
Does anyone have a detailed idea of how to accomplish this issue? What technology is used? Temp tables, indexes, or any other features used to provide this functionality.