Re: Oracle: why should one specify the width of a number column?

From: astaroth <>
Date: Fri, 9 Oct 2009 12:26:03 -0700 (PDT)
Message-ID: <>

VTR250 wrote:
> 100 takes up less space than 9999 -- so it is correct: you really do
> save 1 byte. If I'm reading your post wrongly, what specifically is
> incorrect in the original statement? This is a digression, however,
> because we're all in agreement that you don't need to save the byte, but
> the size limit is a good idea because it helps stop junk data getting
> in.

Two things:
100 takes up less space than 9999 - that's right, because 100 has less significant digits.

And what I did disagree with:
>> > Even though I know a NUMBER(4) for a year, or a NUMBER(3) for a >> > person's age actually takes less bytes of storage than NUMBER,

A NUMBER(4) for a year will take exactly the same amount of bytes of storage than NUMBER! Precision and scale are only constraints that prevent some values from being stored, but do not affect how much space you need to store it.

9999 takes 3 bytes whether stored in NUMBER, NUMBER(4), NUMBER(10) or NUMBER(12,2) - but Oracle will just reject this value for NUMBER(3) column.

Received on Fri Oct 09 2009 - 21:26:03 CEST

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