Re: Column information

Hi, guys,

On Thu, May 4, 2017 at 10:54 AM, Adrian Klaver
<adrian(dot)klaver(at)aklaver(dot)com> wrote:
> On 05/04/2017 07:44 AM, Tom Lane wrote:
>>
>> Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com> writes:
>>>
>>> Alright I see that, but why does my example show a
>>> numeric_precision_radix of 10?
>>
>>
>>> Is there some transition point where it goes from base 10 to base 2?
>>
>>
>> In PG, "numeric" always has radix 10, because the underlying
>> implementation is decimal, and all other numerical types such as int and
>> float have radix 2, because the underlying implementation is binary.
>> Other DBMSses could perhaps do it differently.
>>
>> Hmm ... you could argue that numeric_precision_radix is telling you
>> something about the type's arithmetic behavior independently of what
>> the particular column's maximum-precision-if-any is. That's not how
>> the SQL spec defines it, but that's really what it's doing.
>>
>>> Also why does the OPs query show anything when the data_type is integer?
>>
>>
>> The point is that our integers are 32-bit integers, not some other size.
>> If you try it on bigint or smallint columns, you'll get other answers.
>
>
> Got it thanks, I was being too literal in my interpretation of numeric.

So basically what you are all saying is that since the value "32"
contains 2 digits:
"3" and "2" the column radix will contain "2". And it is not the
actual representation
of the number 32 the radix applies to.

Am I right?

But then what purpose does this column solves?

Just curious...

Thank you.

>
>
>>
>> regards, tom lane
>>
>
>
> --
> Adrian Klaver
> adrian(dot)klaver(at)aklaver(dot)com