Is this standard? (was: hierarchical database...)

In article <8p99el$ubj$1_at_nnrp1.deja.com>,   Mark Greene <greenemj_at_my-deja.com> wrote:

[snip]
> Hmmm... not quite equivalent. The db I'm doing is from my coin
> collection, and I'm using the defacto cataloging method for the hobby:
>
> Country
> Denomination
> Series
> Type
> Variety
> Year
> Variation
>

I've created all of the above tables, but without any references to each other. I've then created the following tables:

cntry_denom
denom_series
series_type
type_vrty
vrty_vrtn

With each table containing only two colums, those being the primary keys of the tables being linked.

This way, once a country is selected, then the valid denominations for that country can be selected, the valid types for the denomination, etc. down the heirarchy.

Is this a standard way of linking information via tables? It avoids repeating foriegn keys in the primary tables, keeps the table sizes small, and will actually be fairly straightforward to access programmatically.

All input is appreciated.

--
Mark
Burning our skins to be renewed, but never hiding the charred look as
we forever age ourselves without reason.
 -- Hardrock Llewynyth  in a.g.


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