sql> create or replace procedure test(p1 in varchar2,p2 out varchar2  ) is
2  begin
3    select p1||' procedure executed！' into p2 from dual ;
4  end;
5  /
procedure created

require 'dbi'

db_read_str = 'begin test(?, ?); end;'
dbh = dbi.connect('dbi:oci8:tnsdbname', 'username', 'password')
sth_db = dbh.prepare(db_read_str)
sth_db.bind_param(1, 'test:',''*50)  # allow for up to 50 chars
sth_db.bind_param(2, ' ' * 100)      # allow for up to 100 chars
sth_db.execute
str = sth_db.func(:bind_value, 2)
puts str
dbh.disconnect

c:\>ruby -cw call_proc_test.rb
syntax ok

c:\>

c:\>ruby  call_proc_test.rb
test: procedure executed！

c:\>