In QlikView you have an Load-Script where you decide what you load (SQL, xls, csv, html, qvd) and how you want to do it.
In scenarios where actuality is not relevant you can start your loadscript manually when ever you need it.
If you need near-time data you can automate the load process on the server and the publisher delivers the new preloaded data when it is available.
In both cases you can also work with incremental loads.