Re: Performance question

Oops, I made a mistake, you were confirming my original quesiton, that yes, the length of the column is stored with the data, can anyone else confirm this? Is this documented in any Oracle documentation? I can't find it anywhere.

Thanks,

Eric

"Eric Levinson" <nospam_at_nospam.com> wrote in message news:ie8J8.4757$3w2.21689_at_typhoon.sonic.net...
> Thanks for your answer, Howard, however it was not what I was asking.
>
> For CHAR(10), what you stated applies.
> For VARCHAR(10), the column is variable size regardless of the "10"
>
> My question is, if I store the word 'test' in a VARCHAR2(10) column, is
> there another piece of data ONLY for varchar2 or any other datatype which
is
> variable width which would store the number 4, so that LENGTH returns this
> value, or is this data NOT stored, and everytime LENGTH function is
called,
> the database has to count characters in the VARCHAR2 field till it reaches
> some end of field mark (like hex FF)
>
>
> Thanks,
> Eric
>
>
>
> "Howard J. Rogers" <dba_at_hjrdba.com> wrote in message
> news:ad14go$gkk$1_at_lust.ihug.co.nz...
> > The format of a row is: row header, column length - value; column
length -
> > value; column length - value; and so ad infinitum (nearly).
> >
> > The length of a field is stored as an attribute within the row. If it
was
> > Name Char(10) it would be stored as :10:Smith-----: If it was Name
> > varchar2(10) it would be stored as :5:Smith:
> >
> > Regards
> > HJR
> >
> > "Eric Levinson" <nospam_at_nospam.com> wrote in message
> > news:DjUI8.4416$3w2.19388_at_typhoon.sonic.net...
> > > When a VARCHAR2 type column is defined, how does the LENGTH function
get
> > the
> > > length of the varchar contained in the column? Does it count up the
> > number
> > > of bytes to some end of string marker, or is there an internally held
> and
> > > maintained attribute of varchar which maintains the size?
> > >
> > > Reason why I am asking, there might be a performance hit to use LENGTH
> if
> > it
> > > has to calculate it every time.
> > >
> > > Any help would be appreciated
> > >
> > > oracle at levinsong dot com
> > >
> > >
> >
> >
>
>
Received on Wed May 29 2002 - 12:33:47 CDT