class Sequel::ODBC::Dataset

def convert_odbc_value(v)
  # When fetching a result set, the Ruby ODBC driver converts all ODBC 
  # SQL types to an equivalent Ruby type; with the exception of
  # SQL_TYPE_DATE, SQL_TYPE_TIME and SQL_TYPE_TIMESTAMP.
  #
  # The conversions below are consistent with the mappings in
  # ODBCColumn#mapSqlTypeToGenericType and Column#klass.
  case v
  when ::ODBC::TimeStamp
    db.to_application_timestamp([v.year, v.month, v.day, v.hour, v.minute, v.second])
  when ::ODBC::Time
    Sequel::SQLTime.create(v.hour, v.minute, v.second)
  when ::ODBC::Date
    Date.new(v.year, v.month, v.day)
  else
    v
  end
end

def default_timestamp_format
  TIMESTAMP_FORMAT
end

def fetch_rows(sql)
  execute(sql) do |s|
    i = -1
    cols = s.columns(true).map{|c| [output_identifier(c.name), i+=1]}
    columns = cols.map{|c| c.at(0)}
    if opts[:offset] && offset_returns_row_number_column?
      rn = row_number_column
      columns.delete(rn)
    end
    @columns = columns
    if rows = s.fetch_all
      rows.each do |row|
        hash = {}
        cols.each{|n,i| hash[n] = convert_odbc_value(row[i])}
        hash.delete(rn) if rn
        yield hash
      end
    end
  end
  self
end

def literal_date(v)
  v.strftime(ODBC_DATE_FORMAT)
end

def literal_false
  BOOL_FALSE
end

def literal_true
  BOOL_TRUE
end