So, I've connected to an Act DB from an ASP page using the connect string:
strConnect = "Driver={Microsoft Visual FoxPro Driver}; SourceType=DBF; SourceDB=C:\ActTestDB; Exclusive=No;"

I've read from the database, written to the database, updated the database (using the format INSERT INTO filename... [where filename is the name of the .dbf file]) using SQL style programming.

When I insert into the db, I can see the record I added when I do a SELECT query on a webpage, but when I open that Act file, I don't see the record I added until I compress/reindex the database. My conclusion is that I also need to update the .mdx file (which is the index file for the contacts table), but I don't know how to do this. Has anyone had experience doing this, and could you help me out if you have?

By the way, a tip for people who are looking to get started on doing this sort of database manipulation...on INSERT queries, you have to insert on all fields...that is, INSERT INTO file (field1, field2,...,fieldn) Values (...). There are at least 60 fields in the default Act DB. Get the SDK from to read's on page 32 of the .pdf file