From: edk_ruby@... (Edward Kremer)
Date: 2002-03-04T13:37:20+09:00
Subject: DBI ODBC connection on WIN NT has a bug.

DBI ODBC connection on WIN NT has a bug.

Program access_odbc.rb:

   require 'dbi'
   URL = 'DBI:ODBC:expenses'
   dbh = DBI.connect(URL, "", "")
   sth = dbh.prepare('select * from employees')
   sth.execute

   while row = sth.fetch do
	p row
   end

   dbh.disconnect

   produces the following output

>ruby access_odbc.rb
/cygdrive/e/ruby/lib/ruby/site_ruby/1.6/dbi/dbi.rb:714:in `[]': no
implicit conversion from string (TypeError)
	from /cygdrive/e/ruby/lib/ruby/site_ruby/1.6/dbi/dbi.rb:714:in
`column_names'
	from /cygdrive/e/ruby/lib/ruby/site_ruby/1.6/dbi/dbi.rb:714:in
`collect'
	from /cygdrive/e/ruby/lib/ruby/site_ruby/1.6/dbi/dbi.rb:714:in `each'
	from /cygdrive/e/ruby/lib/ruby/site_ruby/1.6/dbi/dbi.rb:714:in
`collect'
	from /cygdrive/e/ruby/lib/ruby/site_ruby/1.6/dbi/dbi.rb:714:in
`column_names'
	from /cygdrive/e/ruby/lib/ruby/site_ruby/1.6/dbi/dbi.rb:695:in
`execute'
	from access_odbc.rb:5
>Exit code: 1

Bug is actually found in the ODBC.rb in the following procedure:

   def column_info
    info = []
    @handle.columns do |col|
      info << {
        'name'       => col.name, 
        'table'      => col.table,
        'nullable'   => col.nullable,
        'searchable' => col.searchable,
        'precision'  => col.precision,
        'scale'      => col.scale,
        'sql_type'   => col.type,
        'type_name'  => DBI::SQL_TYPE_NAMES[col.type],
        'length'     => col.length,
        'unsigned'   => col.unsigned
      }
    end
  rescue ODBCErr => err
    raise DBI::DatabaseError.new(err.message)
  end

This procedure is supposed to return info that is array of hashes but
returns some intermediate result. To fix bug you can insert a single
line of code before &#8220;rescue&#8221; line. Additional line will
be, of course:

	info

This solves the problem and now program produces correct output:

>ruby access_odbc.rb
[12, "890340376", "4356", "Jim", "Pope", "Mr", "3456", "77
Southstreet,", "Phila", "PA", "19307", "USA", "213-241-8833", nil]
>Exit code: 0

Actually I am new user of ruby in the following environment:

WINDOWS NT
RUBY cygwin installation from PragmaticProgrammers site, version 1.6.5
(2001-09-19) [i386-cygwin]

This installation is missing database drivers, in particularly, 

ODBC.so
Oracle.so

I downloaded version of odbc.so compiled at 10/11/2001from
http://www.ch-werner.de/rubyodbc/ and now it is working. I tested it
for Ms Access and ORACLE &#8211; ODBC connections.

I got a feeling that oracle-odbc connection is relatively slow
compared to the similar Perl connection, so it would be desirable to
check how the native connection works.

I am wondering if anybody can share oracle.so driver for described
environment?

(Oracle8i Enterprise Edition Release 8.1.6.0.0)

I do not have currently C compiler on the machine where ORACLE is
installed.

Thanks a lot,

Edward Kremer