ios - ランダム選択で繰り返しなしの SQL ステートメント

Question

sqlite データベースを使用して、iOS でクイズ ゲームを作成しました。質問をランダムに取得して、その回答を正しく返すことはできますが、2 つの質問があります。まず、同じ質問を繰り返さないようにすることは可能ですか? 次に、プレイヤーがプレイしたい質問の数を設定してもらいたいと思います。2番目のものについては、テキストフィールドを使用してアラートビューを正常に作成しましたが、SQLステートメントに値を渡すことは可能ですか? 前もって感謝します。

ランダムな質問に使用するSQLステートメントのコードは次のとおりです。

const char *sql = "SELECT * FROM Questions WHERE Category IS 2 ORDER BY RANDOM() LIMIT 1";

すべてのコードは次のとおりです。

-(NSMutableArray *) categoriesList{
categories = [[NSMutableArray alloc] initWithCapacity:10];
@try {
    NSFileManager *fileMgr = [NSFileManager defaultManager];
    NSString *dbPath = [[[NSBundle mainBundle] resourcePath ]stringByAppendingPathComponent:@"Categories.sqlite"];
    BOOL success = [fileMgr fileExistsAtPath:dbPath];
    if(!success)
    {
        NSLog(@"Cannot locate database file '%@'.", dbPath);
    }
    if(!(sqlite3_open([dbPath UTF8String], &db) == SQLITE_OK))
    {
        NSLog(@"An error has occured: %s", sqlite3_errmsg(db));
    }


    const char *sql = "SELECT * FROM Questions WHERE Category IS 2 ORDER BY RANDOM() LIMIT 1";
    sqlite3_stmt *sqlStatement;
    NSString * insertSQL = [NSString stringWithFormat:
                            @"UPDATE Questions SET Used='NO'"];
    const char * insert_stmt = [insertSQL UTF8String];
    sqlite3_prepare_v2(db, insert_stmt,-1, &sqlStatement, NULL);

    if(sqlite3_prepare(db, sql, -1, &sqlStatement, NULL) != SQLITE_OK)
    {
        NSLog(@"Problem with prepare statement:  %s", sqlite3_errmsg(db));
    }else{

        while (sqlite3_step(sqlStatement)==SQLITE_ROW) {

            Categories * choise = [[Categories alloc] init];

            question.text = [NSString stringWithUTF8String:(char *) sqlite3_column_text(sqlStatement, 1)];

            NSMutableArray  *arary = [[NSMutableArray alloc]init];
            while (arary.count < 4) {
                int value = arc4random()%4+2;
                BOOL isFound = [[arary filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:[NSString stringWithFormat:@"intValue == %d",value]]] count];
                if(!isFound)
                    [arary addObject:[NSNumber numberWithInteger:value]];
            }
            answer1.text = [NSString stringWithUTF8String:(char *) sqlite3_column_text(sqlStatement, [[arary objectAtIndex:0] intValue])];
            answer2.text = [NSString stringWithUTF8String:(char *) sqlite3_column_text(sqlStatement, [[arary objectAtIndex:1] intValue])];
            answer3.text = [NSString stringWithUTF8String:(char *) sqlite3_column_text(sqlStatement, [[arary objectAtIndex:2] intValue])];
            answer4.text = [NSString stringWithUTF8String:(char *) sqlite3_column_text(sqlStatement, [[arary objectAtIndex:3] intValue])];

            NSString * columnName  = [NSString stringWithUTF8String:(char *) sqlite3_column_name(sqlStatement, [[arary objectAtIndex:0] intValue])];

            answer1.tag = ([columnName isEqualToString:@"Answer1"])?999:0;

            columnName = [NSString stringWithUTF8String:(char *) sqlite3_column_name(sqlStatement, [[arary objectAtIndex:1] intValue])];

            answer2.tag = ([columnName isEqualToString:@"Answer1"])?999:0;


            columnName = [NSString stringWithUTF8String:(char *) sqlite3_column_name(sqlStatement, [[arary objectAtIndex:2] intValue])];

            answer3.tag = ([columnName isEqualToString:@"Answer1"])?999:0;


            columnName = [NSString stringWithUTF8String:(char *) sqlite3_column_name(sqlStatement, [[arary objectAtIndex:3] intValue])];

            answer4.tag = ([columnName isEqualToString:@"Answer1"])?999:0;

            answer1btn.tag = answer1.tag;
            answer2btn.tag = answer2.tag;
            answer3btn.tag = answer3.tag;
            answer4btn.tag = answer4.tag;
            [categories addObject:choise];
            [self prepareForIntroAnimation];
            [self performIntroAnimation];
        }
    }
    sqlite3_finalize(sqlStatement);
}
@catch (NSException *exception) {
    NSLog(@"Problem with prepare statement:  %s", sqlite3_errmsg(db));
}
@finally {

    sqlite3_close(db);

    return categories;
}
}