Re: Column information

On 05/04/2017 07:29 AM, Tom Lane wrote:
> Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com> writes:
>> On 05/04/2017 07:00 AM, Tom Lane wrote:
>>> No, certainly not. The radix column says what the units of measurement
>>> are, not that the values in the precision column aren't decimal. So radix
>>> 2 indicates that precision 32 means "32 bits", not "32 decimal digits".
>
>> Alright now I am confused:
>
>> https://www.postgresql.org/docs/9.6/static/infoschema-columns.html
>
>> "numeric_precision cardinal_number
>
>> If data_type identifies a numeric type, this column contains the
>> (declared or implicit) precision of the type for this column. The
>> precision indicates the number of significant digits. It can be
>> expressed in decimal (base 10) or binary (base 2) terms, as specified in
>> the column numeric_precision_radix. For all other data types, this
>> column is null.
>> "
>
> I'm not here to defend the wording in our documentation ;-)
>
> Perhaps this would be clearer if it said "measured in ... digits" rather
> than "expressed in ... terms"?
>
> It should probably also say "identifies a numeric type of restricted
> precision", since for example it'll be null for a column that's
> NUMERIC but has no typmod.

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?

Also why does the OPs query show anything when the data_type is integer?

>
> regards, tom lane
>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com