On 2021-06-07 10:20:22 -0700, David G. Johnston wrote: > On Sun, Jun 6, 2021 at 11:55 PM Peter J. Holzer <[email protected]> wrote: > On 2021-06-03 22:51:55 +0200, Marc Millas wrote: > > postgres 12 with postgis. > > on a table we need a primary key and to get a unique combinaison, we > need > > 3 columns of that table: > > 1 of type integer, > > 1 of type text, > > 1 of type geometry > > > > creating the PK constraint doesn work: > > I find that if a natural primary key candidate is so complex, it is > usually better to use a surrogate key. > > > You make this sound like an either-or proposition,
While he is talking about *a* primary key, it should be *the* primary
key. There can be only one (that's why it is the primary key).
There can be several unique keys, though.
> but personally it takes a very exceptional circumstance to forgo
> defining a unique natural key.
True, but not what he's talking about.
hp
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_ | Peter J. Holzer | Story must make more sense than reality.
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