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Compressing ADC<br />
Won’t have all tricks of prior slide in any current DBMS<br />
But we can usually compress adjoined dimension columns to<br />
small ints: use UDF for mapping so Store.Nation = ‘United<br />
States’ maps to small int 7<br />
create function NATcode (nat char(18)) returns small int<br />
…<br />
return case nat<br />
when ‘United Kingdom’ then 1<br />
…<br />
when ‘United States’ then 7<br />
…<br />
end<br />
Now a user can write:<br />
Select … from POS where S_Nation = Natcode(‘United States’)…<br />
Natcode will translate ‘United States’ to the int 7; thus all ADC<br />
can be two-byte (or less) small ints with proper UDFs defined<br />
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