Doesn’t this depend on the file driver you are using though? Well, sort of. The “MSSQL” file driver is I think just an extra abstraction over the ODBC driver for Clarion and the advantages/differences seem to be a little hard to define. I thought it was related mostly to SQL Native Client but I seem to recall this was disproved some time back. See also this related topic.
Yeah, so that is about making sure what you are doing is helpful to the query optimizer but the advantage might depend on the kind of workload you are throwing at the server. e.g. If you have one query that takes 10 minutes to complete then no amount of parametization will help but if you have a query that gets run a zillion times then the more you can do to help the server optimize for the execution of that query the better.
However, I am pretty sure that anything you run via the Clarion file drivers is already being done via prepared statements and you don’t have much (any?) control over how that happens. On the other hand, I think you gain a bit of safety against SQL Injection attacks (don’t quote me, still test for this!).
If he is around @Dennis has lots of good tips on this kind of thing. He might also be able to point you in the direction of interacting more directly with the server.
Probably the speed problem with Clarion is not so much related to the parametization but the shoving of everything through cursors, or more specifically matching the odbc cursor type to your workload requirements). I would think the best thing you can do is optimize the heck out of your SQL code and do as much as possible on the server. For example, in your NetTalkCentral post it seems like you are pulling a bunch of data back from the server into a clarion memory table. Unless you absolutely need that data client side you would be better to up your sql-fu and get all your processing done in a stored procedure or something and only return the results. Plus, you can then, within your stored procedures, start to consider optimizations like parametization of queries 
Documentation on the Clarion File Drivers would be nice or even better, being able to poke around at their code and actually know what they are doing.
Absolutely, I love it!! 
