Re: does a table always need a PK?

Heikki Tuuri wrote:
>
> If we have a quantum mechanical system where electrons are
> indistinguishable, would it not be natural to create a table of electrons
> without a primary key?

... and forget about the Pauli Exclusion Principle? :-)

But apart from that, if all electrons are indistinguishable then in fact there is actually just one electron, isn't there? So your question should actually have been:

  If we have a quantum mechanical system with always one electron, would it   not be natural to create a table of electrons without a primary key?

The answer would be of course "no" because this table has a unique candidate key: the empty set.

• Jan Hidders