Re: Vague idea for allowing per-column locale

On Tue, 14 Aug 2001, Tatsuo Ishii wrote:

> Storing everything as Unicode is not a good idea, actually. First,
> Unicode tends to consume more storage space than other character
> sets. For example, UTF-8, one of the most commonly used encoding for
> Unicode consumes 3 bytes for Japanese characters, while SJIS only
> consumes 2 bytes. Second, a round trip converison between Unicode and
> other character sets is not always possible. Third, sorting
> issue. There is no convenient way to sort Unicode correctly.

UTF-16 can handle most Japanese characters in two bytes, afaict. Generally
it seems that utf8 encodes European text more efficiently on average,
whereas utf16 is better for most Asian languages. I may be mistaken, but I
was under the impression that sorting of unicode characters was a solved
problem. The IBM ICU class library (which does have a C interface), for
example, claims to provide everything you need to sort unicode text in
various locales, and uses utf16 internally:

http://oss.software.ibm.com/developerworks/opensource/icu/project/index.html

The licence is, I gather, the X licence, which presumably is compatible
enough with BSD; not that I would necessarily advocate building this into
postgres at a fundamental level, but it demonstrates that it can be done.

Note that I'm not speaking from experience here, I've just read the docs,
and a book on unicode, never actually performed a Japanese-language (or
any other non-English language) sort, so no need to take me too seriously
:).

> Tatsuo Ishii

Tim

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Tim Allen          tim@proximity.com.au
Proximity Pty Ltd  http://www.proximity.com.au/ http://www4.tpg.com.au/users/rita_tim/