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List:       sas-l
Subject:    Re: three dimensional tables
From:       Sigurd Hermansen <HERMANS1 () WESTAT ! COM>
Date:       2005-02-28 18:20:20
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John:
Years ago I did some programming in SAS/IML, apl, and matrix languages.
Based on that experience, I find it difficult to understand why data
cubes and hypercubes have become popular again. When RDBMS's began doing
indexing effectively in the background, I quit writing multidimensional
arrays. I don't believe that I have used a multidimensional array in a
SAS program during the last ten years.

SAS, in fact, makes it very easy to create implicit arrays with
meaningful subscript values. A composite key, say k1, k2, k3, acts as a
set of subscripts of an array. Substituting other values for integers
does not change the function of the composite key. One can use integers
if one prefers. SQL reflexive joins even make it possible to compare
intervals of subscripts.

Programmers accustomed to reading across a page may prefer a data model
of an cube to a table, but the same information maps to either
structure. At the abstract machine level, data structures in general do
not follow the data structure models that programmers use. Where array
subscripts have meaning, I would prefer to see their values embedded in
data; where subscripts have no meaning, I would prefer to get the same
functionality from indexes.
Sig



-----Original Message-----
From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU] On Behalf Of
John F. Regus
Sent: Sunday, February 27, 2005 4:14 AM
To: SAS-L@LISTSERV.UGA.EDU
Subject: three dimensional tables


Does SAS allow for the creation of three dimension tables.  It would be
subsripted as such.  VAR1(x1, y1, z1), VAR(x2,y2,z2), etc.

Or are only two dimensional arrays supported VAR(x,y), etc.

TIA
JR

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