Re: One byte integer support

But Postgres 'char' is just an alias for 'character',
so it will won't be just a single byte. And I've
already accounted for padding and alignment in my
structures and using bytes instead of shorts would
result in a significant savings both in memory as well
as disk. I don't understand why Postgres doesn't have
a single-byte int support. Even MySQL does.

--- Kris Jurka <books@ejurka.com> wrote:

>
>
> On Thu, 6 Jan 2005, Keith Hankin wrote:
>
> > Is there any way to support one byte integers? I
> am
> > using JDBC and would like to use setByte() method
> to
> > populate values of a single-byte integer valued
> > column. I tried defining the column as
> character(1),
> > but I get the error message:
> >
> > Exception in thread "main"
> > org.postgresql.util.PSQLException: ERROR: value
> too
> > long for type character(1)
> >
> > I don't see how a byte is too long for
> character(1).
>
> Character is a textual data type, byte is a numeric
> value so when you set
> a byte value of say 145 to a text type you get the
> string '145' which is
> three characters.
>
> Note that character(1) does not take up one byte of
> space on disk.  It is
> a one character field, not one byte.  Multibyte
> character sets may need
> more than one byte to store a single character, so
> this is variable byte
> length field that takes up at least 5 bytes of
> space.  4 bytes of length
> data and then the actual data bytes.
>
> > Is there any data type like MySQL's tinyint?
> >
>
> Possibly the system type "char" (needs the quotes),
> but I have no idea how
> that will work with the JDBC driver.  Going with
> smallint may be the best
> thing to do.  Before assuming that a tinyint would
> actually save you space
> you need to make sure you take into account padding
> and alignment.
>
> Kris Jurka
>




__________________________________
Do you Yahoo!?
The all-new My Yahoo! - What will yours do?
http://my.yahoo.com