title: First normal form and temporal data
body: <p>The first normal form says that row ordering should not matter.
  Does this mean that a table with date as part of the key is not 1NF?
  e.g.
  Consider a table of ticker prices where date/time is part of the PK. In this case, you get the last price by ordering the data by date and selecting the top 1 row.
  Does this mean that for to fulfill 1NF you need to split the table into:
  1) TickerCurrentPrice (1 row per ticker)
  2) TickerHistoricalPrice
  Thanks</p>