Re: Unicode support

On Tuesday 14 April 2009 07:07:27 Andrew Gierth wrote:
> FWIW, the SQL spec puts the onus of normalization squarely on the
> application; the database is allowed to assume that Unicode strings
> are already normalized, is allowed to behave in implementation-defined
> ways when presented with strings that aren't normalized, and provision
> of normalization functions and predicates is just another optional
> feature.

Can you name chapter and verse on that?

I see this, for example,

6.27 <numeric value function>

5) If a <char length expression> is specified, then
Case:
a) If the character encoding form of <character value expression> is not UTF8,
UTF16, or UTF32, then let S be the <string value expression>.
Case:
i)
If the most specific type of S is character string, then the result is the
number of characters in the value of S.
NOTE 134 — The number of characters in a character string is determined
according to the semantics of the character set of that character string.
ii)
Otherwise, the result is OCTET_LENGTH(S).
b) Otherwise, the result is the number of explicit or implicit <char length
units> in <char length expression>, counted in accordance with the definition
of those units in the relevant normatively referenced document.

So SQL redirects the question of character length the Unicode standard. I
have not been able to find anything there on a quick look, but I'm sure the
Unicode standard has some very specific ideas on this. Note that the matter
of normalization is not mentioned here.