Re: [Caml-list] PostgreSQL-OCaml 1.0.1

[Richard Jones <rich@annexia.org>]

On Fri, Jan 30, 2004 at 12:56:43PM +0000, Benjamin Geer wrote:
> Richard Jones wrote:
> >It throws Sql_error when it can determine an error.
> 
> Another thing I forgot to bring up about error handling.  If an error 
> occurs, you generally want to roll back the transaction.  If you're 

You might want to have a look at the code to see if it does what you
want.

In practice, writing mainly CGI scripts and standalone scripts as we
do, this is never a problem for us.  Our code is structured like this:

  let dbh = (* open connection, or get connection from pool *)

  (* do work with the connection, never checking for any exceptions *)

  dbh#commit

In the case of a standalone script, the script dies (exits) when an
error occurs, printing the SQL error message.  The database then
automatically rolls back the connection.  This is just the behaviour
of PostgreSQL - if a connection is closed in the middle of a
transaction then the database gets rolled back.

In the case of CGI scripts, the Dbi Pool code automatically performs a
dbh#rollback just before taking back a connection and placing it back
into the pool.  So if an error did occur before the commit, then the
database gets rolled back.

Rich.

-- 
Richard Jones. http://www.annexia.org/ http://www.j-london.com/
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