module Sequel::Oracle::Dataset::ArgumentMapper

def map_to_prepared_args(bind_vars)

but with the keys converted to strings.
Return a hash with the same values as the given hash, 
def map_to_prepared_args(bind_vars)
  prepared_args.map{|v, t| [bind_vars[v], t]}
end

def prepared_arg(k)

arguments.
Oracle uses a : before the name of the argument for named 
def prepared_arg(k)
  y, type = k.to_s.split("__", 2)
  prepared_args << [y.to_sym, type]
  i = prepared_args.length
  LiteralString.new(":#{i}")
end

def prepared_arg?(k)

Always assume a prepared argument. 
def prepared_arg?(k)
  true
end