Looking for change password in iphone application sdk using sqlite

i am trying to change old password in my iphone application my code is below please help how can i do ....

-(IBAction)matchpassword{ //sqlite3_stmt *updateStmt; sqlite3 *database; const char *dbpath = [databasePath UTF8String]; sqlite3_stmt *statement;

if (sqlite3_open(dbpath, &database) == SQLITE_OK)
{
    NSString *querySQL = [NSString stringWithFormat: @"SELECT password FROM password WHERE password=\"%@\"", txtOldPass.text];

    const char *query_stmt = [querySQL UTF8String];

    if (sqlite3_prepare_v2(database, query_stmt, -1, &statement, NULL) == SQLITE_OK)
    {
        if (sqlite3_step(statement) == SQLITE_ROW)
        {
            NSString *addressField = [[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement, 0)];
            if(updatepass == nil){
                if([txtNewPass.text isEqualToString:txtConfPass.text]){
                    const char *sql ="update password Set password = ? Where pk = ?";

                    if(sqlite3_prepare_v2(database, sql, -1, &updatepass, NULL)!=SQLITE_OK)
                        NSAssert1(0,@"Error while creating update statement. '%s'.",sqlite3_errmsg(database));
                }

            //  Globle *objupdate = [[Globle alloc]initWithPK:0];
            //  objupdate.pass =[[NSString stringWithUTF8String:(char *)sqlite3_column_text(updatepass, 1)]retain];
                //pass = [[NSString stringWithUTF8String:(char *)sqlite3_column_text(login, 1)]retain];
                sqlite3_bind_text(updatepass, 1, [pass UTF8String], -1, SQLITE_TRANSIENT);
                sqlite3_bind_int(updatepass, 2, pk);



                if(SQLITE_DONE != sqlite3_step(updatepass)){
                    NSAssert1(0,@"error while updating  '%s'",sqlite3_errmsg(database));
                }
                else{
                    sqlite3_last_insert_rowid(database);
                }
                sqlite3_reset(updatepass);
                sqlite3_finalize(updatepass);
                [objectToEdit setValue:txtOldPass forKey:self.keyOfTheFieldToEdit];
                passwordViewController *FBController = [[passwordViewController alloc] initWithNibName:@"passwordViewController" bundle:nil];
                [self.view addSubview:FBController.view]; 

            }
            txtOldPass.text = addressField;
            status.text = @"Match found";
            [addressField release];
        }
        else 
        {
            //status.text = @"Match not found";
            txtOldPass.text = @"";
            //phone.text = @"";
            UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"UIAlertView" message:@"Wrong username or password" delegate:self cancelButtonTitle:@"ok" otherButtonTitles:nil];
            [alert show];
            [alert release];

        }
        sqlite3_finalize(statement);
    }
    sqlite3_close(database);
}

}