On 22 Dec 2009, at 10:55am, Jean-Denis Muys wrote: > On 12/22/09 11:31 , "Sylvain Pointeau" <sylvain.point...@gmail.com> wrote: > >> Imagine that I want to query my database for a certain type of word, >> the user could enter ü or ue and I will display the corresponding items... >> >> It cannot be done in the application layer... >> > > Or maybe it can... You could for example maintain in your application, > possibly in a SQLite table for that purpose, all equivalence classes of all > characters. > > The obvious optimisation is to omit an equivalence class when it's a > singleton. > > So you are left with a few equivalence classes that may look like this: > > ü, ue > ä, ae, æ > e, é, è, ê, ë > > (or whatever).
But at that distance you might as well get rid of vowels entirely. That is what SOUNDEX and Metaphone are for: <http://en.wikipedia.org/wiki/Soundex> Not only do they make up for minor spelling errors, but they also compensate for different character sets. You can see some details of German equivalents here: <http://www.sggee.org/misc/soundex.html> <http://de.wikipedia.org/wiki/Kölner_Phonetik> As you can see, these things should definitely be done in the application layer. Store both forms of your text: the original text and the encoded form. Simon. _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
