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Home -> Community -> Usenet -> comp.databases.theory -> Re: Proposal: 6NF
Relations can be defined to work as follows:
> A domain D1 presents severals values and operators applyable on these values.
> A un-ary relation R1 extracts and RESTRICTS possible values and operators. Such relation R1 is synonyme with type.
> The method for restricting the values drawn from domain D1 and populate R1 is called a constraint. Such constraint can be of arbitrary complexity.
> The relation value of R1 *consitute* a new derived domain D2 which only include values permissible by the method that restrict (or constraint).
Hope this helps... Received on Thu Oct 12 2006 - 05:38:08 CDT
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