Array vs Temporary Tables, benchmark testing

[Jason Wainwright <JasonW@LIMON.CO.ZA>]

Hi All

There are many routines that need data to be stored and/or sorted.  I was
wondering whether, performance wize, if arrays are better than temporary
tables.  I am led to believe that some DBMS' will only create indexes if
many rows are being used (e.g. Sybase may have 1000).  And so with all the
overhead ,such as server and network resources,  how expensive are arrays,
lookups and temporary tables in sqr?  And how can I measure performance?
And what performance issues are there to consider?

THanx