ray_apps_blog

If you are using Rails 1.2.3 with Oracle database then you might find that text attributes (which map to Oracle CLOB data type) get invalid default values – e.g. you might find that when you create new record it will get “empty_clob()” as default text attribute value.

I found out that this issue is corrected in current edge Rails. As I still primarily use Rails 1.2.3 I created the following patch according to the changes that are done in edge Rails. You can put it in environment.rb file or better put into a separate file and require it in environment.rb file.

# RSI: text defaults handling from http://dev.rubyonrails.org/ticket/7344 & http://dev.rubyonrails.org/changeset/6090
module ActiveRecord::ConnectionAdapters
  class OracleAdapter
    def quote(value, column = nil) #:nodoc:
      # RSI: patched
      if value && column && [:text, :binary].include?(column.type)
        %Q{empty_#{ column.sql_type.downcase rescue 'blob' }()}
      else
        super
      end
    end

    def columns(table_name, name = nil) #:nodoc:
      (owner, table_name) = @connection.describe(table_name)
      table_cols = <<-SQL
        select column_name as name, data_type as sql_type, data_default, nullable,
               decode(data_type, 'NUMBER', data_precision,
                                 'FLOAT', data_precision,
                                 'VARCHAR2', data_length,
                                  null) as limit,
               decode(data_type, 'NUMBER', data_scale, null) as scale
          from all_tab_columns
         where owner      = '#{owner}'
           and table_name = '#{table_name}'
         order by column_id
      SQL
      select_all(table_cols, name).map do |row|
        limit, scale = row['limit'], row['scale']
        if limit || scale
          row['sql_type'] << "(#{(limit || 38).to_i}" + ((scale = scale.to_i) > 0 ? ",#{scale})" : ")")
        end
        # clean up odd default spacing from Oracle
        if row['data_default']
          row['data_default'].sub!(/^(.*?)\s*$/, '\1')
          row['data_default'].sub!(/^'(.*)'$/, '\1')
          # RSI: patched
          row['data_default'] = nil if row['data_default'] =~ /^(null|empty_[bc]lob\(\))$/i
        end
        OracleColumn.new(oracle_downcase(row['name']),
                         row['data_default'],
                         row['sql_type'],
                         row['nullable'] == 'Y')
      end
    end

    # RSI: added
    def add_column_options!(sql, options) #:nodoc:
      # handle case of defaults for CLOB columns, which would otherwise get "quoted" incorrectly
      if options_include_default?(options) && (column = options[:column]) && column.type == :text
        sql << " DEFAULT #{quote(options.delete(:default))}"
      end
      super
    end

  end
end