On 5 August 2011 10:55, Dan Kennedy <danielk1...@gmail.com> wrote:
>
> On 08/05/2011 02:58 PM, Martin Gill wrote:
> >
> > CREATE VIRTUAL TABLE full_text USING FTS3 (id,text)
> > INSERT INTO full_text VALUES ('1', 'I have a foréign character.')
>
> SQLite does not recognize upper/lower-case mappings for non-ASCII
> characters. That is why querying for "HAVE" works but "FORÉIGN"
> does not. If you need upper/lower case mapping for non-ASCII characters,
> you will need to use the ICU extension.
>
That may be part of the problem. System.Data.SQlite isn't compiled with ICU, so
I cannot check that quickly. I do though get exactly the same odd
behaviour using
the porter tokenizer.
> > SELECT id, text FROM full_text WHERE NOT(text = @p1) AND text MATCH @p2
> >
> > p1 = "foréign"
> > p2 = "FORÉIGN"
> >
> > Not using parametrized SQL also returns a correct result.
>
> I don't see how either the query above or a version that uses SQL
> literals could be returning any rows.. Not with the "CREATE VIRTUAL
> TABLE" as it stands above. Unless you specify the ICU tokenizer (or
> some other tokenizer that understands non-ASCII upper/lower case),
> "FORÉIGN" should not match the row in table "full_text".
>
Except that it does.
While I gave the unicode value, e-acute is ASCII 130, and capital
e-acute is ASCII 144.
That puts them on the extended ascii chart ( 128 < c <= 255 ) and I
believe all western
European codepages will have the characters.
Create the database as indicated and run
SELECT id, text FROM full_text WHERE NOT(text = 'foréign') AND text
MATCH 'FORÉIGN'
and you'll get a result. At least on my British installation of Windows.
Here's the C# code that demonstrates the issue.
My initial attachment seems to have been cut off:
============================================
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SQLite;
using System.Reflection;
using System.IO;
namespace sqlitetests
{
class Program
{
static void Main(string[] args)
{
SQLiteConnection connection = CreateOpenDB();
Test1(connection);
Test2(connection);
Test3(connection);
Test4(connection);
Console.ReadKey();
}
static SQLiteConnection CreateOpenDB()
{
if (File.Exists("test.sq3"))
{
File.Delete("test.sq3");
}
SQLiteConnectionStringBuilder csb = new
SQLiteConnectionStringBuilder();
csb.DataSource = @"test.sq3";
csb.Version = 3;
SQLiteConnection connection = new SQLiteConnection(csb.ToString());
connection.Open();
SQLiteCommand command = connection.CreateCommand();
command.CommandText = "CREATE VIRTUAL TABLE full_text
USING FTS3 (id,text, tokenize=porter)";
command.ExecuteNonQuery();
command = connection.CreateCommand();
command.CommandText = "INSERT INTO full_text VALUES ('1',
'I have a foréign character.')";
command.ExecuteNonQuery();
return connection;
}
static void Test1(SQLiteConnection connection)
{
SQLiteCommand theCommand = new SQLiteCommand(connection);
string tableName = "full_text";
theCommand.CommandText = string.Format("SELECT id, text
FROM {0} WHERE NOT(text = @source) AND text MATCH @query", tableName);
StringBuilder sb = new StringBuilder();
string query = "FORÉIGN";
string sourceText = "foréign";
SQLiteParameter param = theCommand.CreateParameter();
param.Value = query;
param.ParameterName = "query";
param.DbType = System.Data.DbType.String;
theCommand.Parameters.Add(param);
param = theCommand.CreateParameter();
param.Value = sourceText.TrimEnd();
param.ParameterName = "source";
param.DbType = System.Data.DbType.String;
theCommand.Parameters.Add(param);
SQLiteDataReader reader = theCommand.ExecuteReader();
Console.WriteLine("{0} : {1}",
MethodInfo.GetCurrentMethod().Name, reader.HasRows);
}
static void Test2(SQLiteConnection connection)
{
SQLiteCommand theCommand = new SQLiteCommand(connection);
string tableName = "full_text";
theCommand.CommandText = string.Format("SELECT id, text
FROM {0} WHERE NOT(text = @s) AND text MATCH @q", tableName);
StringBuilder sb = new StringBuilder();
string query = "FORÉIGN";
string sourceText = "foréign";
SQLiteParameter param = theCommand.CreateParameter();
param.Value = query;
param.ParameterName = "q";
param.DbType = System.Data.DbType.String;
theCommand.Parameters.Add(param);
param = theCommand.CreateParameter();
param.Value = sourceText.TrimEnd();
param.ParameterName = "s";
param.DbType = System.Data.DbType.String;
theCommand.Parameters.Add(param);
SQLiteDataReader reader = theCommand.ExecuteReader();
Console.WriteLine("{0} : {1}",
MethodInfo.GetCurrentMethod().Name, reader.HasRows);
}
static void Test3(SQLiteConnection connection)
{
SQLiteCommand command = new SQLiteCommand(connection);
command.CommandText = string.Format("SELECT id, text FROM
{0} WHERE NOT(text = @p1) AND text MATCH @p2", "full_text");
SQLiteParameter param1 = command.CreateParameter();
param1.Value = "FORÉIGN";
param1.ParameterName = "p1";
param1.DbType = System.Data.DbType.String;
command.Parameters.Add(param1);
SQLiteParameter param2 = command.CreateParameter();
param2.Value = "foréign";
param2.ParameterName = "p2";
param2.DbType = System.Data.DbType.String;
command.Parameters.Add(param2);
SQLiteDataReader reader = command.ExecuteReader();
Console.WriteLine("{0} : {1}",
MethodInfo.GetCurrentMethod().Name, reader.HasRows);
}
static void Test4(SQLiteConnection connection)
{
SQLiteCommand theCommand = new SQLiteCommand(connection);
string tableName = "full_text";
theCommand.CommandText = string.Format("SELECT id, text
FROM {0} WHERE NOT(text = @source) AND text MATCH @query", tableName);
StringBuilder sb = new StringBuilder();
string query = "HAVE";
string sourceText = "have";
SQLiteParameter param = theCommand.CreateParameter();
param.Value = query;
param.ParameterName = "query";
param.DbType = System.Data.DbType.String;
theCommand.Parameters.Add(param);
param = theCommand.CreateParameter();
param.Value = sourceText.TrimEnd();
param.ParameterName = "source";
param.DbType = System.Data.DbType.String;
theCommand.Parameters.Add(param);
SQLiteDataReader reader = theCommand.ExecuteReader();
Console.WriteLine("{0} : {1}",
MethodInfo.GetCurrentMethod().Name, reader.HasRows);
}
}
}
============================================
--
Regards,
Martin
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