Hi all,

Here is the first proposal for a database independent interface (Dbi)
for Ocaml.  The file "dbi.mli" is attached below.  The code and some
experiments with Mysql can be downloaded from

   http://www.umh.ac.be/math/an/software.php#x4-60005

Some sample code:

  module DB = Dbi_mysql  (* select db module *)
  let t = new DB.row_conversion
  let ( ++ ) = Dbi.(^^)

  let dbh = DB.connect ~host ~pwd "my database" in
  let q = dbh#prepare "SELECT Salary, Name from employees" in
  let res = dbh#raw_exec q [||] in
  let s = res#fold (t#int ++ t#string) (fun sum s _ -> sum + s) 0 in
  dbh#disconnect;
  s

This release is to foster discussions, it is not to be considered as
clean/ready-to-use code.  In particular, some points I'd like feedback
on:

* I think the scheme for "parameter binding" (for encoding and
  decoding) is quite convenient (and prevents the often forgotten
  escaping for encoding).  Does it also fit the needs of your
  applications?

* The way "parameter binding" is implemented (a la scanf) has some
  performance penalty.  Is it possible to come up with a better
  implementation or better ideas?  Is it possible to use Camlp4 to
  reduce the cost while providing the same convenience?

* Are you happy with the methods provided by Dbi.result and the
  interaction between "step by step" and "iteration/folding" schemes
  (stateful object)?

* What basic SQL conversion functions should be provided by all DBs
  (class type Dbi.conversion)?

* What exceptions should be defined in order not to have too many of
  them yet to offer flexibility?  The exceptions defined so far are a
  bit basic, they need to be refined.

I am available for questions if things are unclear (but don't hold
your breath, I am pretty busy).

Cheers,
ChriS