sqlite_prepare_v2不返回SQLITE_OK

Question

我一直在试图挽救高分到数据库，并已经发生故障许多过去的一周，我不知道为什么它不工作。我不断收到“问题的准备声明”，并拒绝插入到信息数据库。我曾与数据库管理器检查，以确保没有与SQL语句中的错字，当查询的管理器上运行，它工作正常 - 这只是竟然放弃了我的问题iphone。如果任何人都可以请尽快查看，并看到一些不妥之处，可以让我知道，我将不胜感激！

- (NSMutableArray *) saveLocal {
    NSLog(@"save local database");
    @try {
        [self checkDB];
        sqlite3_stmt *sqlStatement2;


        NSString *sqlS = [NSString stringWithFormat:@"INSERT INTO localHighscore (difficulty, score, uname, puzzles, multiplier, oneshots, hints) VALUES (%i,%i,\"%@\",%i,%i,%i,%i)",[[MySingleton sharedMySingleton] goDifficulty],[[MySingleton sharedMySingleton] goScore],_player, [[MySingleton sharedMySingleton] goPuzzles], [[MySingleton sharedMySingleton] goMultiplier], [[MySingleton sharedMySingleton] goOneshots], [[MySingleton sharedMySingleton] goHints]];
        NSLog(@"%@",sqlS);
        const char *sql = [sqlS UTF8String];


        if(sqlite3_prepare_v2(localHighscore, sql, -1, &sqlStatement2, NULL) == SQLITE_OK)
        {
            sqlite3_step(sqlStatement2);
            sqlite3_reset(sqlStatement2);
            sqlite3_finalize(sqlStatement2);
            NSLog(@"save complete");
        } else {
            NSLog(@"Problem with prepare statement");
        }  
        sqlite3_close(localHighscore);
    }@catch (NSException *exception) {
        NSLog(@"An exception occured: %@", [exception reason]);
    }@finally{
        NSLog(@"DB Loaded!");
    }
}

这里是CHECKDB方法，检查是否存在数据库，并创建一个，如果它不

- (void)checkDB {
    NSString *docsDir;
    NSArray *dirPaths;

    // Get the documents directory
    dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

    docsDir = [dirPaths objectAtIndex:0];

    // Build the path to the database file
    databasePath = [[NSString alloc] initWithString: [docsDir stringByAppendingPathComponent: @"localHighscore.sqlite"]];

    NSFileManager *filemgr = [NSFileManager defaultManager];    
    if ([filemgr fileExistsAtPath: databasePath ] == NO)
    {
    const char *dbpath = [databasePath UTF8String];
        NSLog(@"file was not found");
        if (sqlite3_open(dbpath, &localHighscore) == SQLITE_OK)
        {
            NSLog(@"db open");
            char *errMsg;
            const char *sql_stmt = "CREATE TABLE IF NOT EXISTS localHighscore(pk INTEGER PRIMARY KEY AUTOINCREMENT, difficulty TINYINT, score MEDIUMINT, uname VARCHAR(255), puzzles TINYINT, multiplier TINYINT, oneshots TINYINT, hints TINYINT)";

            if (sqlite3_exec(localHighscore, sql_stmt, NULL, NULL, &errMsg) != SQLITE_OK)
            {
                NSLog(@"Failed to create table");
            }
            sqlite3_close(localHighscore);            
        } else {
            NSLog(@"Failed to open/create database");
        }
    }
    [filemgr release];
}

先谢谢您的帮助！

Answer 1

一对夫妇的想法：

1. 你似乎没有试图使用数据库之前调用sqlite3_open。
2. 每当你得到一个错误，你应该看看sqlite3_errmsg，例如

   if (sqlite3_exec(localHighscore, sql_stmt, NULL, NULL, &errMsg) != SQLITE_OK)
   {
       NSLog(@"Failed to create table: %s", sqlite3_errmsg(localHighscore));
   }

3. 也许无关你的问题，但使用stringWithFormat一般情况下不应建立一个SQL语句（至少如果您有任何文本字段）。使用?占位符的SQL，然后用sqlite3_bind_xxx功能。

   const char *sql = "INSERT INTO localHighscore (difficulty, score, uname, puzzles, multiplier, oneshots, hints) VALUES (?,?,?,?,?,?,?)";
   
   if(sqlite3_prepare_v2(localHighscore, sql, -1, &sqlStatement2, NULL) == SQLITE_OK)
   {
       if (sqlite3_bind_int(sqlStatement2, 1, [[MySingleton sharedMySingleton] goDifficulty]) != SQLITE_OK) {
           NSLog(@"bind 1 failed: %s", sqlite3_errmsg(localHighscore));
       }
   
       if (sqlite3_bind_int(sqlStatement2, 2, [[MySingleton sharedMySingleton] goScore]) != SQLITE_OK) {
           NSLog(@"bind 2 failed: %s", sqlite3_errmsg(localHighscore));
       }
   
       if (sqlite3_bind_text(sqlStatement2, 3, [_player UTF8String], -1, NULL) != SQLITE_OK) {
           NSLog(@"bind 3 failed: %s", sqlite3_errmsg(localHighscore));
       }
   
       // repeat this bind process for each variable
   
       if (sqlite3_step(sqlStatement2) != SQLITE_DONE) {
           NSLog(@"step failed: %s", sqlite3_errmsg(localHighscore));
       }
   
       // reset not needed (doesn't hurt, but not needed unless you're going to re-use it
       // sqlite3_reset(sqlStatement2);
   
       sqlite3_finalize(sqlStatement2);
       NSLog(@"save complete");
   } else {
       NSLog(@"Problem with prepare statement: %s", sqlite3_errmsg(localHighscore));
   }  
   sqlite3_close(localHighscore);

   如果你觉得这句法笨重，那么也许可以考虑使用FMDB，从而简化您的SQL互动。但要十分警惕stringWithFormat与SQL（如果插入的字符串有引号，则sqlite3_prepare会失败，从理论上说，您的应用程序受到SQL注入攻击等）。
4. 顺便说一句，你不应该[filemgr release]，因为你不拥有它。

Answer 2

我看到“sqlite3_prepare_v2（）”功能，当SQL语句包含像“booleanfield =假”，而不是“booleanfield = 0”的条件下返回“一般错误”（错误代码= 1）。在SQLiteStudio程序的SQL执行箱相同的SQL语句中使用漠然第一或比较的第二种形式提供了良好的效果。