Question

好的，所以我的SQLite查询越来越好......但显然还不是主人。

我试图遍历这个返回的数组，而我得到的每个条目都是0。

以下是进行查询调用并返回结果的内容（此特定查询当前应返回6行数据）：

-(NSMutableArray *)getMyAthleteList
{
NSMutableArray *athleteList = [[NSMutableArray alloc] init];

NSString *getAthleteListSQL = [[NSString alloc] initWithFormat:@"SELECT * FROM athletes"];

sqlite3_stmt *selectStmt;

if (sqlite3_prepare_v2(database, [getAthleteListSQL UTF8String], -1, &selectStmt, nil)==SQLITE_OK)
{
    while (sqlite3_step(selectStmt)==SQLITE_ROW)
    {
        //NSLog(@"Adding athletes to the array");
        Athletes *athlete_array = [Athletes alloc];
        athlete_array.athlete_image = [[NSString alloc] initWithFormat:@"%d",sqlite3_column_int(selectStmt, 0)];
        athlete_array.athlete_id = [[NSString alloc] initWithFormat:@"%d",sqlite3_column_int(selectStmt, 1)];
        athlete_array.athlete_name = [[NSString alloc] initWithFormat:@"%d",sqlite3_column_int(selectStmt, 2)];
        athlete_array.school_name = [[NSString alloc] initWithFormat:@"%d",sqlite3_column_int(selectStmt, 3)];
        athlete_array.sport_name = [[NSString alloc] initWithFormat:@"%d",sqlite3_column_int(selectStmt, 4)];
        athlete_array.athlete_flag = [[NSString alloc] initWithFormat:@"%d",sqlite3_column_int(selectStmt, 5)];
        [athleteList addObject:athlete_array];
    }
}
else
{
    NSLog(@"Did not make a good query");
}

return athleteList;
}

现在这是我在调用和循环时所做的事情：

AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];

NSArray *myAthleteList = [[NSArray alloc] initWithArray:[appDelegate getMyAthleteList]];

for (Athletes *athlete in myAthleteList) {
    NSLog(@"Athlete Name: %@", athlete.athlete_name);
    NSLog(@"Athlete ID: %@", athlete.athlete_id);
}

输出是：

运动员姓名：0 运动员ID：0

我的字符串（athlete_name，athlete_id等）都已正确定义（在我的Athletes.m和.h文件中）。

我确信我错过了一些简单的东西，但任何帮助都会受到高度赞赏。

谢谢！

Answer 1

您是否希望这样的行从DB返回一个字符串？

athlete_array.athlete_name = [[NSString alloc] initWithFormat:@"%d",
                              sqlite3_column_int(selectStmt, 2)];

如果是这样，您可能需要查看sqlite3_column_text或text16

请参阅：http://www.sqlite.org/capi3ref.html#sqlite3_column_blob

您也可能想要使用它，因为它返回一个const char *：

[[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(...)

例如，这是我的一个样本中的类似片段：

contact = [[Contact alloc] init];
while (sqlite3_step(statement) == SQLITE_ROW)
{
    int idx = 0;

    NSNumber *idField = [NSNumber numberWithLongLong:sqlite3_column_int64(statement, idx++)];
    [contact setId:idField];

    NSString *nameField = [[NSString alloc] initWithUTF8String:
                           (const char *) sqlite3_column_text(statement, idx++)];
    [contact setName:nameField];

    NSString *addressField = [[NSString alloc] initWithUTF8String:
                            (const char *) sqlite3_column_text(statement, idx++)];
    [contact setAddress:addressField];

    NSString *phoneField = [[NSString alloc] initWithUTF8String:
                            (const char *) sqlite3_column_text(statement, idx)];
    [contact setPhone:phoneField];

    NSLog(@"id: %@", [contact id]);
    NSLog(@"name: %@", [contact name]);            
    NSLog(@"address: %@", [contact address]);
    NSLog(@"phone: %@", [contact phone]);

    // Code to do something with extracted data here

    [nameField release];
    [phoneField release];
    [addressField release];
}

另外，请考虑保存已编译的语句＆amp; selectStmt并调用sqlite3_reset再次使用。它在那时编译成字节代码，你不需要一遍又一遍地解析和编译你的sql语句。

请参阅：http://www.sqlite.org/capi3ref.html#sqlite3_prepare

完成语句后（完全如果你将其保存），不要忘记调用sqlite3_finalize。

对于iOS 5中的所有条目，SQLite3查询返回0

1 个答案: