Re: SET? What?

On Mon, Sep 02, 2002 at 06:20:05PM -0600, Dan Ostrowski wrote:
> Ok, I have been pouring over stuff in my PostgreSQL book and the online
> docs and stuff.. but I can't nail down what the hell a "SET" is.  I hear
> you guys use "tuples" a lot and I know SET defines somekind of type with
> tuples, but what ARE They and how would one set them?
>
> I kinda assumed ( probably wrong ) they were like either the SET or ENUM
> of MySQL, but now I am just lost. What ARE these tuples?

This has come up before. A 'set' is the mathematical term for a group of
tuples (i almost said 'set of tuples' there :) ). So loosly:

tuple == row
table == set
attribute == column

Although a table is more about persistant storage whereas the result of a
join can't really be called a table. I guess that's why people use 'set' in
that instance.

Hope this helps,
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> There are 10 kinds of people in the world, those that can do binary
> arithmetic and those that can't.