Re: Column information

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.

regards, tom lane