Re: Informix limitations, should we be using Oracle?

Andrew Hamm wrote:

> Obnoxio The Clown wrote:
> >
> > 255 byte limit on varchar fields -- still true (I think)
> >
>
> One point that should be shared with Oraclers regarding varchars on
> Informix...
>
> I've noticed that Oraclers are obsessed with using varchars of one kind or
> another, and from what I read about the page allocation strategies, it is
> indeed worthwhile to use them in Oracle.
>
> However, with informix, plain old CHAR types are highly optimised (in the
> engine and the way they are handled, I mean), and they also behave very
> varcharish anyway. Trailing blanks are disregarded amongst other things, and
> Informix varchars miss out on some high-performance optimisations. In a
> typical database, the wasted space is far less than you might imagine... So
> if you ever dabble with Informix, it really is OK to abandon varchars for
> CHARs. Just a small cultural difference to adapt to.

The reason in Oracle the CHAR data type is almost never used has nothing to do with storage or performance. It has to do with the fact that in Oracle CHAR fields ALWAYS right pad with spaces to the full length of the column which makes string comparison's very messy unless all data in the field is guaranteed to be the exact size of the field. And, needless to say, it doesn't help indexes either.

Daniel Morgan Received on Thu Oct 17 2002 - 17:26:37 CEST