Opening multiple databases with SQLite

@interface database : NSObject {
        sqlite3 * db;
        sqlite3_stmt * query;
        NSString *queryString;
        NSString *dbPath;
}

- (void) opendb;
- (BOOL)attach_user_databases;

@end

@implementation database

- (void) opendb
{
        dbpath = [[NSBundle mainBundle] pathForResource:@"levels" ofType:@"db"];
        sqlite3_open([dbpath UTF8String], &db);

        [self attach_user_databases];

         sqlite3_prepare_v2(db, [queryString UTF8String], -1,  &query, NULL);
}

- (BOOL)attach_user_databases
{
    int dbcount = 0, result;
    NSFileManager *fm = [NSFileManager defaultManager];
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSDirectoryEnumerator *docs = [fm enumeratorAtPath:documentsDirectory];
    NSString *file;
    while ((file = [docs nextObject])) {
        if ([[file pathExtension] isEqualToString:@"sqlite3"]) {
            ++dbcount;
            NSString *fullPath = [documentsDirectory stringByAppendingPathComponent:file];
            sqlite3_stmt *attach;
            sqlite3_prepare_v2(db,[[NSString stringWithFormat:@"ATTACH DATABASE '%@' AS 'DB%i'",fullPath,dbcount] UTF8String], -1, &attach, NULL);
            sqlite3_step(attach);
            sqlite3_finalize(attach);
        }
    }
    if (dbcount == 0) {
        queryString = @"SELECT * FROM levels WHERE ROWID=?";
        return NO;
    }
    else {
        sqlite3_stmt *cview;
        NSMutableString *createView = [NSMutableString stringWithString:@"CREATE TEMP VIEW LV AS SELECT * FROM levels"];
        for (int i=1;i<=dbcount;++i) {
            [createView appendFormat:@" UNION SELECT * FROM DB%i.levels",i];
        }
        sqlite3_prepare_v2(db, [createView UTF8String], -1, &cview, NULL);
        sqlite3_step(cview);
        sqlite3_finalize(cview);
        queryString = @"SELECT * FROM LV WHERE ROWID=?";
        return YES;
    }
}

@end