This also made me think of prepared statements.

It would be more readable to have all the values in their respective place in the SQL string, rather than have a bunch of question marks followed by all the values bunched together at the end. e.g. this:

    PreparedStatement query = SQL."SELECT * FROM users WHERE firstname=\{firstName} and lastname=\{lastName} and email=\{email}";

rather than:

    query = client.prepare("SELECT * FROM users WHERE firstname=? and lastname=? and email=?",
                           firstName, lastName, email);