Re: Fwd: Silly question about numbering of rows?

On Tue, 13 Mar 2001, Ken Corey wrote:

> Moderator, please don't approve the other two posts I've made...just this one
> is plenty...;^)

Not a moderated list.

> I have a table like this:
>
>         id |      make | model | year  | value
> ---------+-----------+--------+-------+-------
>        57 |            2 |        0 |       4 |  4750
>        57 |            2 |        3 |       4 |  4750
>        57 |            2 |        0 |       0 |  4750
>        57 |            2 |        0 |       3 |  4750
>        57 |            2 |        3 |       0 |  4750
>        57 |            2 |        3 |       3 |  4750
>          2 |            2 |        0 |       3 |  4750
>          2 |            2 |        3 |       3 |  4750
>          2 |            2 |        0 |       4 |  4350
>          2 |            2 |        3 |       4 |  4350
>          2 |            2 |        0 |       0 |  4750
>          2 |            2 |        0 |       5 |  4750
>          2 |            2 |        3 |       0 |  4750
>          2 |            2 |        3 |       5 |  4750

The potential for duplicate records is rampant here.  What is the primary
key?  Do these values use foreign keys?

> Everything is working swimmingly, except for the numbering magic.  As you can
> see there are several variations of data in that table, so I can't use a
> serial on the table directly.

Why not?  The serial number can be used exclusively for identifying a
unique row.  That's definitely the easiest way to do this numbering.

> Further, this table is likely to change on a minute by minute basis, so I
> don't want to create a permanent numbering that will just have to be changed.

Ah, that is a problem.

> It sounds easiest to me to just punt and number the rows as they are returned
> in my calling application...

That might be the way to go, if the ordering and numbering is changing
constantly.

-- Brett
                http://www.chapelperilous.net/~bmccoy/
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