Re: Relational Database: Union Compatibility Question

"TonY" <tonyosborne_a_at_hotmail.com> wrote in message news:1be98fcb.0411291700.39ffb4bb_at_posting.google.com...
> In other reference, it is stated that two relations are union
> compatibles if they have the same degree and the *same attribute
> names* and domains. The *order of attributes is immaterial*.

May I suggest somewhat unconventional perspective? http://www.dbazine.com/tropashko7.shtml
Like an intersection, union could be considered as redundant operator. Although, set operator utility was never challenged, from relational expressivity perspective it appears like no set operators is necessary at all! Received on Tue Nov 30 2004 - 02:36:21 CET