iOS SQLite SELECT with UTF 8 characters - ios

Question

I've been reading all questions related to SQlite encoding with no success, so I'll try to ask about my specific case.
I have an iOS app with a SQLite database prepopulated.
This SQLite has been converted from a MySQL database.
Both the SQLite and MySQL databases have UTF8 enconding (the conversion process set the default sqlite enconding to UTF8)
If I open my sqlite database with Firefox SQlite Manager I can read all the content without problems, and all UTF8 chars are shown properly, so I guess everything was converted correctly.
But, when I try to perfom a select with UTF8 chars inside, the query fails.
This is the method where I perform the queries:
- (NSArray *)performQuery:(NSString *)query
{
static sqlite3 *db;
sqlite3_stmt *resultado;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *writableDBPath = [documentsDirectory stringByAppendingPathComponent:#"mydatabase.sqlite"];
const char *dbpath = [writableDBPath UTF8String];
if (sqlite3_open(dbpath, &db) == SQLITE_OK)
{
printf("%s\n", [query UTF8String]);
int codigo = sqlite3_prepare_v2(db,[query UTF8String],[query length],&resultado,NULL);
if (codigo == SQLITE_OK)
{
NSMutableArray *result = [NSMutableArray array];
while (sqlite3_step(resultado) == SQLITE_ROW)
{
NSMutableArray *row = [NSMutableArray array];
for (int i = 0; i < sqlite3_column_count(resultado); i++)
{
int colType = sqlite3_column_type(resultado, i);
id value;
if (colType == SQLITE_TEXT)
{
value = [[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(resultado, i)];
if ([value isEqualToString:#"(null)"] || [value isEqualToString:#""] || (value == nil) || [value isKindOfClass:[NSNull class]])
{
value = #"";
}
}
else if (colType == SQLITE_INTEGER)
{
int col = sqlite3_column_int(resultado, i);
value = [NSNumber numberWithInt:col];
}
else if (colType == SQLITE_FLOAT)
{
double col = sqlite3_column_double(resultado, i);
value = [NSNumber numberWithDouble:col];
}
else if (colType == SQLITE_NULL)
{
value = [NSNull null];
}
else
{
NSLog(#"ERROR: DataBase - performQuery - Campo desconocido");
}
[row addObject:value];
}
[result addObject:row];
row = nil;
}
sqlite3_finalize(resultado);
sqlite3_close(db);
resultado = nil;
return result;
}
else
{
NSLog(#"ERROR [%d](%s): %#", codigo, sqlite3_errmsg(db), query);
}
}
else
{
NSLog(#"ERROR: No se pudo abrir la base de datos");
}
sqlite3_close(db);
db = nil;
resultado = nil;
return nil;
}
And this is the method where I call performQuery:
- (int) getIdForItem:(NSString *)item
{
NSString *query = [NSString stringWithFormat:#"SELECT item_id FROM table_items WHERE item_name=\"%#\"", item];
NSLog(#"QUERY:\n%#", query);
NSArray *answer = [self performQuery:query];
if([answer count] > 0)
return [[[answer objectAtIndex:0] objectAtIndex:0] intValue];
return -1;
}
If I make this call:
[self getIdForItem:#"Camión"];
This is the output:
QUERY:
SELECT item_id FROM table_items WHERE item_name="Camión"
SELECT item_id FROM table_items WHERE item_name="Camión"
ERROR [1](unrecognized token: ""Cami√≥n"): SELECT item_id FROM table_items WHERE item_name="Camión"
This error is produced in the method:
sqlite3_prepare_v2(db,[query UTF8String],[query length],&resultado,NULL)
So, Why is Camión interpreted as Cami√≥n in sqlite_prepare_v2? Both the query and the sqlite database are using UTF8, so I guess I'm missing something...

Answer 1

Well, the rmaddy's solution worked perfectly for me. What I've done is:
PerformQuery is almost the same, it receives a new argument:
- (NSArray *)performQuery:(NSString *)query withArgument:(NSString *)arg
Just after the sqlite3_prepare_v2 I've made the bind:
int codigo = sqlite3_prepare_v2(db,[query UTF8String],[query length],&resultado,NULL);
if (codigo == SQLITE_OK)
{
sqlite3_bind_text(resultado, 1, [arg UTF8String], -1, SQLITE_TRANSIENT);
NSMutableArray *result = [NSMutableArray array];
while (sqlite3_step(resultado) == SQLITE_ROW)
And finally, I call this method this way:
- (int) getIdForItem:(NSString *)item
{
NSString *query = #"SELECT item_id FROM table_items WHERE item_name=?1";
NSLog(#"QUERY:\n%#", query);
NSArray *answer = [self performQuery:query];
if([answer count] > 0)
return [[[answer objectAtIndex:0] objectAtIndex:0] intValue];
return -1;
}