We have a web application that we want to use to write some data to PI. It is an application used for other purposes, but we would like to be able to occasionally write some data to the PI data archive. In some cases we would like to write data directly from the web application, and in other cases the data will be stored in SQL and written to PI in batches at a later time. I know there is PI AF SDK, PI Web API etc. What is the advised method?