Re: Arrays and "goodness" in RDBMSs (was Re: join of - Mailing list pgsql-general

In response to both Andrew Gould and Ron Johnson...

If arrays are not natural in the organization of
your data, don't use them. That is the guideline.

If the array defines something specific they are
very natural.  The confusion could be that arrays
are abstract types.

Specific implementations which use arrays might
be clearer.  For example, a definition of a polygon
is an array of Points.  Points, themselves are an
array.

(The actual postgreSQL implementation of polygons and points
doesn't use the newer cleaner array abstraction, I think.
But if I were reimplementing them, I would build on
top of the new array capabilities.  The point is to show
an array structured object which makes sense in context.)

Of course you can denomalize via arrays, but it tends
to make things harder for you.  And I believe the
same thing is true for denormalized integer columns.

elein
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On Fri, Aug 15, 2003 at 02:20:18PM -0500, Ron Johnson wrote:
> On Fri, 2003-08-15 at 13:32, elein wrote:
> > PostgreSQL is an ORDBMS, not just an RDBMS.
>
> But y'all are talking about the SQL standard here.
>
> > A column holds a type of value.  Any kind.  The
> > structure and operands define the type.  The data
> > defines the value.  This holds true for simple types
> > like an integer or complex types like an array.
> >
> > The database data is relatively "type blind" in an
> > ORDBMS.  It uses the standard overloaded operands
> > to determine the type of function to perform for
> > all of the usual RDBMS utilities.
> > Constraints, triggers, sorting, etc. all apply.
> >
> > That's what the ORDBMS stuff can give you.
> > Arrays are a natural extension.
> >
> > Arrays don't necessarily imply denormalization.
> > It depends on how you use them.  The same rule
> > applies for integers.
>
> I dunno 'bout that...
>
> > elein
> >
> > On Fri, Aug 15, 2003 at 01:13:52PM -0500, Ron Johnson wrote:
> > >
> > > Why are arrays even mentioned in the the same breath wrt relations
> > > DBMSs?  Aren't they an anathema to all we know and love?
>
> --
> +---------------------------------------------------------------+
> | Ron Johnson, Jr.        Home: ron.l.johnson@cox.net           |
> | Jefferson, LA  USA                                            |
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> | "Man, I'm pretty.  Hoo Hah!"                                  |
> |    Johnny Bravo                                               |
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