Alban Hertroys wrote:
If you _do_ need this table (because you want to constrain your
statistical data to only contain a specific set of years, or because you
need a quick list of available years to select from): Make the year
primary key and drop the artificial index.
Years are perfectly fine data to constrain on, and it saves you the
joins with that table (the foreign key constraint constrains your data
sufficiently).
You may want to constrain your years further by adding a check
constraint, fe. CHECK (year > 1900).
The same argument goes for the country names, but I generally don't like
to have text data for primary key.
Ah, but there is a standardised list of country-codes ideal for the DBA
since the code is (usually) easily understandable.
http://en.wikipedia.org/wiki/ISO_3166
The only problem might be if historical data uses old boundaries (e.g.
Soviet Union, Yugoslavia).
--
Richard Huxton
Archonet Ltd
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