Re: NUMERIC x VARCHAR

On 8/11/2004 2:21 AM, Scott Marlowe wrote:

> On Tue, 2004-08-10 at 23:42, Er Galvão Abbott wrote:
>> Greetings.
>>
>> I have a question regarding performance of certain datatypes:
>>
>> I have a field where I will store my clients phone numbers. I know
>> that this field will never exceed 15 characters, and I will store only
>> numbers here (no dashes, dots, etc...), so I was wondering:
>>
>> Wich type is faster: NUMERIC(15,0) or VARCHAR(15)? Are there any
>> storage differences between them?
>
> Since numerics are stored as text strings, the storage would be
> similar. Numerics, however, may be slower since they have more
> constraints built in. If you throw a check constraint on the
> varchar(15) then it will likely be about the same speed for updating.

They are stored as an array of signed small integers holding digits in
base-10000, plus a precision, scale and sign. That's somewhat different
from text strings, isn't it?

Jan

>
> text type with a check contraint it what i'd use. That way if you want
> to change it at a later date you just drop and recreate your constraint.
>
>
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