The DataAssist Extension includes the query builder functionality. The DataAssist Search wizard can be accessed by going to Insert -> WebAssist -> DataAssist -> DataAssist Search Wizard.
Before starting the DataAssist Search Wizard, you should create your results page with a basic unfiltered recordset, and add the results display to the page.
With your results page open, start the DataAssist search wizard to create the search page that will be used to filter the recordset.
WebAssist Extensions do use a transaction model, instead they use a trigger model, see the "WebAssist Triggers: Unleash the Power" PDF document on the learning resources page for more details:
If there are features you do not see in the WebAssist Extensions that you would like the engineers to consider for future upgrades, please post these ideas to the wishlist forum.