Comment 1946 added to page datatype.html of version 7.4

Author: XYZ <XYZ@X.XOM>
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Will Numeric(1000,2) take the maximum disk space needed to store
1000 digits? Or will it take only as much as needed to store the
current number?

Why isn't there a way to make a NUMERIC(scale) i.e. NUMERIC(2) that
have 2 places after the point, but can be of any size?
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Manual page: http://wwwmaster.postgresql.org/docs/7.4/static/datatype.html
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