How should you handle database errors in Express with MongoDB?

Wrap every database call in a try/catch, log the real error server-side, and return a generic message with an appropriate HTTP status code.

try {
  // insert / update / delete / find
} catch (error) {
  console.error(error);
  res.status(500).json({
    message: 'server error while handling request'
  });
}

Security: Never send raw error messages to clients - they may reveal database structure. Log detailed errors server-side, send generic messages to clients.