Re: protocol change in 7.4 - Mailing list pgsql-hackers

From korry
Subject Re: protocol change in 7.4
Date
Msg-id 5.1.0.14.0.20021107164245.043844c8@pop.starband.net
Whole thread Raw
In response to Re: protocol change in 7.4  (snpe <snpe@snpe.co.yu>)
Responses Re: protocol change in 7.4  (snpe <snpe@snpe.co.yu>)
List pgsql-hackers
> > b)  Send a decoded version of atttypmod - specifically, decode the
> > precision and scale for numeric types.
> >
>I want decode type,length,precision and scale

Type is returned by PQftype(), length is returned by PQfsize().  Precision 
and scale are encoded in the return value from PQfmod() and you have to 
have a magic decoder ring to understand them. (Magic decoder rings are 
available, you just have to read the source code :-)

PQftype() is not easy to use because it returns an OID instead of a name 
(or a standardized symbol), but I can't think of anything better to return 
to the client.   Of course if you really want to make use of PQftype(), you 
can preload a client-side cache of type definitions.  I seem to remember 
seeing a patch a while back that would build the cache and decode precision 
and scale too.
 PQfsize() is entertaining, but not often what you really want (you really 
want the width of the widest value in the column after conversion to some 
string format - it seems reasonable to let the client applicatin worry 
about that, although maybe that would be a useful client-side libpq function).




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