Roberto,
>Though I cannot use DLLs since it is an iPhone iOS (MacOSX)
>operational system.
I made it DLL by default at build time since it fits my needs. You can
still compile the extension (or part of it) as a standard .o obj and
statically link it into your application.
>I was hoping for a collation callback that is called for all
>characters, not only the first.
A collation always works on the full arguments it is supplied with,
i.e. on the whole strings that are to ba collated. This behavior is
expected and fully docuented, like Igor also points out in his recent
reply.
>Shouldn't sqlite3_create_collation be called for every single character?
No it has to be called once for each connection and every external (not
already defined by default in the SQLite core) collation function you
require.
> Let's say the comparing names are "São Paulo" and "Santos".
> -> SELECT * FROM Game WHERE TeamHome = 'SANTOS' COLLATE anyCIAI;
I have no idea what anyCIAI means in this context. The extension I
proposed offers 4 new collation functions (NOCASE which overrides the
builtin NOCASE, UNACCENTED, NAMES and NUMERICS). Since these
internally use a Windows call, you can't use their code as is. What I
would do in your situation is write a new collation relying on the
unaccenting internal functions provided in the extension.
>The LOG function shows a comparison between S and other first char
>only only:
>
>41 65 A - 53 83 S = -18
>43 67 C - 53 83 S = -16
>46 70 F - 53 83 S = -13
>53 83 S - 53 83 S = 0
>49 73 I - 53 83 S = -10
>46 70 F - 53 83 S = -13
>50 80 P - 53 83 S = -3
>43 67 C - 53 83 S = -16
>47 71 G - 53 83 S = -12
>I was expecting it to go further in the comparison:"São Paulo" and
>"Santos" should LOGS - Sã - ao - n -> stops here, not what your looking for
>When using it on ORDER BY, it is clear that only the first char is
>compared.
I don't know what LOG / LOGS are in this context.
If you also need to search names with uncertain spelling, you can also
use my typos() function to perform a fuzzy search. Here's a sample of
its use on a decently populated ZipCodes table (848207 rows):
select pays, zip, ville, region from allcountries where typos(ville,
'saopaul%') < 3 group by pays, ville, region
RecNo Pays Zip Ville Region
----- ---- --------- ------------------------ --------------------------
1 AR 6221 LA PAULINA LA PAMPA
2 AU 2031 St Pauls New South Wales
3 BR 64670-000 São Julião Piaui
4 BR 01000-000 São Paulo Sao Paulo
5 BR 97980-000 São Paulo das Missões Rio Grande do Sul
6 BR 69600-000 São Paulo de Olivença Amazonas
7 BR 59460-000 São Paulo do Potengi Rio Grande do Norte
8 ES 22281 La Paul Aragon
9 ES 22471 Laspaules Aragon
10 ES 07691 Sa Taulera Baleares
11 FR 29400 Lampaul Guimiliau Bretagne
12 FR 29810 Lampaul Plouarzel Bretagne
13 FR 29830 Lampaul Ploudalmezeau Bretagne
14 FR 33390 St Paul Aquitaine
15 FR 61100 St Paul Basse-Normandie
16 FR 87260 St Paul Limousin
17 FR 88170 St Paul Lorraine
18 FR 65150 St Paul Midi-Pyrenees
19 FR 60650 St Paul Picardie
20 FR 06570 St Paul Provence-Alpes-Cote D'Azur
21 FR 73170 St Paul Rhone-Alpes
22 FR 02300 St Paul Aux Bois Picardie
23 FR 81220 St Paul Cap De Joux Midi-Pyrenees
24 FR 82400 St Paul D Espis Midi-Pyrenees
>>> snip >>>
68 FR 11320 St Paulet Languedoc-Roussillon
69 FR 30130 St Paulet De Caisson Languedoc-Roussillon
70 FR 43350 St Paulien Auvergne
71 GB EC4 St Paul's (null)
72 GB BR5 St Paul's Cray (null)
73 GB SG4 St Paul's Walden (null)
74 HU 3714 Sajópálfala Borsod-Abaúj-Zemplén
75 IN 281307 Sahpau Uttar Pradesh
76 IN 328027 Saipau Rajasthan
77 IN 171006 Sanjauli Himachal Pradesh
78 IT 39050 St.Paul Trentino-Alto Adige
79 PK 47701 Sanpal Norhern Punajb Rawalpindi
80 PT 8900-121 Sapal Faro
81 PT 4560-042 Sopal Porto
82 PT 2705-738 São Julião Lisboa
83 PT 7300-469 São Julião Portalegre
84 PT 4560-197 São Julião Porto
85 PT 4950-854 São Julião Viana do Castelo
86 PT 5400-754 São Julião de Montenegro Vila Real
87 PT 5300-871 São Julião de Palácios Bragança
88 PT 2664-503 São Julião do Tojal Lisboa
89 PT 3230-023 São Paulo Coimbra
90 PT 4610-370 São Paulo Porto
91 PT 6160-130 São Paulo Baixo Castelo Branco
92 PT 6160-131 São Paulo Cima Castelo Branco
93 RE 97460 St Paul (null)
Result obtained by full table scan in 1.7s on a 3-year old PC.
--
<mailto:j...@q-e-d.org>j...@antichoc.net
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