From: Michael Neumann <mneumann@...>
Date: 2005-01-01T00:34:30+09:00
Subject: Re: [bug] DBD::ODBC

jc wrote:
> I've run into a small bug with DBD::ODBC. The following code:
> 
> require 'dbi'
> dbh = DBI.connect("DBI:ODBC:dsn", "user", "pass")
> puts dbh.columns('table').collect { |c| c.name }
> 
> produced the following error:
> 
> /ruby/lib/ruby/site_ruby/1.8/DBD/ODBC/ODBC.rb:127 in 'columns'
> undefined method '-' for nil:NilClass (NoMethodError
> 
> This relates to the following line in ODBC.rb (line 127)
> 
> info['precision'] = row['COLUMN_SIZE'] - (row['DECIMAL_DIGITS'] || 0)
> 
> It appears this needs to be changed to the following:
> 
> info['precision'] = (row['COLUMN_SIZE'] || 0) - (row['DECIMAL_DIGITS']
> || 0)
> 

maybe it's even better to return nil, if column_size is not set. 
because, imagine decimal_digits is set, then a negative value is returned.

The following is now commited to SVN (see patch below).u

Regards,

   Michael

Index: ODBC.rb
===================================================================
--- ODBC.rb     (revision 415)
+++ ODBC.rb     (working copy)
@@ -124,7 +124,8 @@
        info['type_name'] = row['TYPE_NAME']
        info['sql_type']  = row['DATA_TYPE']
        info['nullable']  = row['NULLABLE']
-      info['precision'] = row['COLUMN_SIZE'] - (row['DECIMAL_DIGITS'] || 0)
+      cs = row['COLUMN_SIZE']
+      info['precision'] = cs ? (cs - (row['DECIMAL_DIGITS'] || 0)) : nil
        info['scale']     = row['DECIMAL_DIGITS']
      end