Hypertable migration causing problem with rails 2.3.8

Question

I am using Hypertable db with the front end of HyperRecord. There were some bugs that i fixed in it. But now migrations get stuck me. When ever i do migrate it shows the error:

rake aborted!
undefined method `select_rows' for #<ActiveRecord::ConnectionAdapters::HypertableAdapter:0xb6f791c4>
.rvm/gems/ruby-1.8.7-p352@r2.3.8/gems/activerecord-2.3.8/lib/active_record/connection_adapters/abstract/database_statements.rb:27:in `select_values'

When i look into the code or ruby on rails actice_record. It shows.

  # Returns an array of arrays containing the field values.
  # Order is the same as that returned by +columns+.
  def select_rows(sql, name = nil)
  end
  undef_method :select_rows

I tried to remove these functions by adding a fix in initializes.

module ActiveRecord
  module ConnectionAdapters
    class HypertableAdapter

      def select_rows(sql, name = nil)
      end
    end
  end
end

Then it came with the error Nil value occurred while accepting array or hash. To fix it i added new method to the fix code.

module ActiveRecord
  module ConnectionAdapters
    class HypertableAdapter

      def select_rows(sql, name = nil)
      end

      def select_values(sql, name = nil)
        result = select_rows(sql, name)
        result.map { |v| v[0] } unless result.nil?
      end
    end
  end
end

then it came with the error:

rake aborted!
You have a nil object when you didn't expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.map
/.rvm/gems/ruby-1.8.7-p352@r2.3.8/gems/activerecord-2.3.8/lib/active_record/migration.rb:421:in `get_all_versions'

Does any one have an idea, what is going on with it?

score 0 · Accepted Answer · answered Sep 09 '11 at 11:23

This code removes all the errors. But now migrations runs well, but do not roll back.

module ActiveRecord
  module ConnectionAdapters
    class HypertableAdapter

      def select_rows(sql, name = nil)
        result = execute(sql)
        rows = []
        result.cells.each { |row| rows << row }
        rows
      end

      def select_values(sql, name = nil)
        result = select_rows(sql, name)
        result.map { |v| v[0] } unless result.nil?
      end
    end
  end
end

When i checked into schema file it shows the following error:

# Could not dump table "teams" because of following StandardError
#   Unknown type '' for column 'ROW'

This fix works perfect for migration up and active record models. Only things remain is the migration rollback. — Nazar Hussain, Sep 12 '11 at 06:58

Hypertable migration causing problem with rails 2.3.8

1 Answers1