Re: what characterset to use?

On Aug 23, 12:19 pm, Ben <bal..._at_comcast.net> wrote:
> On Aug 23, 2:48 pm, sybra..._at_hccnet.nl wrote:
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> > On Thu, 23 Aug 2007 07:02:10 -0700, Ben <bal..._at_comcast.net> wrote:
> > >I'm not saying it is feasible to have a database set to use US7ASCII
> > >as its character set. I'm simply saying that in the scenario that
> > >Sybrand listed, 1 database and 1 client both being set to us7ascii, I
> > >don't see the issue. UNLESS you introduce a client using a different
> > >character set.
>
> > Ok, again
>
> > Client set to US7ASCII
> > Database set to US7ASCII
> > You send an eight bit character.
> > Oracle sees 7 bit client character set, 7 bit server character set
> > --->
> > HEY, I DON'T HAVE TO CONVERT ANY CHARACTER.
> > What will happen if all of a sudden someone decides to export using 7
> > bit NLS_LANG and import into 8 bit database.
>
> > Please don't imply I'm making up fairy tales, I'm talking stories for
> > grown ups!!!!
> > REAL WORLD HORROR STORIES with customers getting GROSS!!!
>
> > And yes: this explanation is on Metalink!!!
>
> > --
>
> I'm not implying anything. I'm trying to understand.
>
> How do you insert an 8 bit character with a 7 bit client into a db
> with a 7 bit character set? Wouldn't that be a square peg round hole
> kind of thing? You of course wouldn't get the 8 bit character back out
> of the 7 bit db.

This is entirely dependent on what tool you are using to insert the data. Sybrand is correct, Oracle simply doesn't check if the sets are equal between client and server. The tool may understand the 8 bits without checking Oracle settings. The tool may be able to get the 8 bits back out. exp will export the 8 bits if, again, you have the client and server set to 7 bits. Then when you import into an 8 bit server setting with the client set to 7 bits, you get the extremely helpful conversion boning or deboning your data, as the case may be.

>
> > >You don't really have control over what character set all the clients
> > >connect with, do you? If you have a client that uses US7ASCII and they
> > >select then update based on results, you could potentially corrupt all
> > >your data. no?
>
> The example in Mr Kyte's book is what I am referring to in my original
> question of not being able to avoid corruption. How can you keep
> someone from setting their NLS_LANG to us7ascii and updating an 8 bit
> or multibyte character field? Anytime that happens you would get a
> replacement character wouldn't you

No, you might get a conversion, depends on whether the 7 bit character is a subset of the 8 bit set, and what the 8 bit character set is.

Keeping people from setting their clients is close to impossible, what you must do is set things up properly so they don't see something wrong and start changing things.

jg

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