Re: [HACKERS] Unicode Normalization
In a context using normalization, wouldn't you typically want to store a normalized-text type that could perhaps (depending on locale) take advantage of simpler, more-efficient comparison functions? Whether you're doing INSERT/UPDATE, or importing a flat text file, if you canonicalize characters and substrings of identical meaning when trivial distinctions of encoding are irrelevant, you're better off later. User-invocable normalization functions by themselves don't make much sense. (If Postgres now supports binary- or mixed-binary-and-text flat files, perhaps for restore purposes, the same thing applies.) David Hudson
Re: [HACKERS] Unicode Normalization
On Sep 24, 2009, at 8:59 AM, Andrew Dunstan wrote: That might be nice, but I'd be wary of a geometric multiplication of text types. We already have TEXT and CITEXT; what if we had your NTEXT (normalized text) but I wanted it to also be case-insensitive? Actually, I don't think it's necessarily a good idea at all. If a user inputs a perfectly valid piece of UTF8 text, we should be able to give it back to them exactly, whether or not it's in normalized form. The normalized forms are useful for certain comparison purposes, but they don't affect the validity of the text. CITEXT doesn't mangle what is stored, just how it's compared. Right, I don't think there's a need for a normalized TEXT type. Best, David -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Unicode Normalization
David E. Wheeler wrote: On Sep 24, 2009, at 6:24 AM, p...@thetdh.com wrote: In a context using normalization, wouldn't you typically want to store a normalized-text type that could perhaps (depending on locale) take advantage of simpler, more-efficient comparison functions? That might be nice, but I'd be wary of a geometric multiplication of text types. We already have TEXT and CITEXT; what if we had your NTEXT (normalized text) but I wanted it to also be case-insensitive? Actually, I don't think it's necessarily a good idea at all. If a user inputs a perfectly valid piece of UTF8 text, we should be able to give it back to them exactly, whether or not it's in normalized form. The normalized forms are useful for certain comparison purposes, but they don't affect the validity of the text. CITEXT doesn't mangle what is stored, just how it's compared. cheers andrew -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Unicode Normalization
On Sep 24, 2009, at 6:24 AM, p...@thetdh.com wrote: In a context using normalization, wouldn't you typically want to store a normalized-text type that could perhaps (depending on locale) take advantage of simpler, more-efficient comparison functions? That might be nice, but I'd be wary of a geometric multiplication of text types. We already have TEXT and CITEXT; what if we had your NTEXT (normalized text) but I wanted it to also be case-insensitive? Whether you're doing INSERT/UPDATE, or importing a flat text file, if you canonicalize characters and substrings of identical meaning when trivial distinctions of encoding are irrelevant, you're better off later. User-invocable normalization functions by themselves don't make much sense. Well, they make sense because there's nothing else right now. It's an easy way to get some support in, and besides, it's mandated by the SQL standard. (If Postgres now supports binary- or mixed-binary-and-text flat files, perhaps for restore purposes, the same thing applies.) Don't follow this bit. Best, David -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Unicode Normalization
On Sep 23, 2009, at 11:08 AM, David E. Wheeler wrote: I looked around and found the Public Software Group's utf8proc project, which even includes some PostgreSQL support (not, alas, for normalization). It has an MIT-licensed C library that offers these functions: Sorry, forgot the link: http://www.public-software-group.org/utf8proc Best, David -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Unicode Normalization
On Sep 23, 2009, at 11:08 AM, David E. Wheeler wrote: I just had a discussion on IRC about unicode normalization in PostgreSQL. Apparently there is not support for it, currently. BTW, the only reference I found on the [to do list](http://wiki.postgresql.org/wiki/Todo ) was: More sensible support for Unicode combining characters, normal forms I think that should probably be changed to talk about the unicode standard support. Best, David -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
