[Exim] Creating SQL local storage

The concept is to create 2 tables...one for headers, one for the body. The
headers table contains an auto_increment index number, the To field, the
From field, the Date field and then the entire header. To/From/Date are all
multiple indices. The body table contains the index number and the body.
That way you can easily do a "JOIN" SQL query when retrieving mail. Also
eliminates the read/write problems associated with appended files.

Question of the day is...how would you go about writing a new local
transport that delivers it to the SQL server? I'd like to make use of the
internal SQL functions (mine is compiled with MySQL support). Sounds pretty
simple in theory...it either succeeds in the "INSERT" queries or it gets
deferred...

If anyone has done this and can provide some code for Exim 4, that'd be
excellent (and save me a LOT of time).

Sam