Question

我已经成功创建了一个TABLE，并尝试在其中插入字符串文本。尝试sqlite3_execute（sqlstatement）时出现错误输出。尝试转换为const char *。我是SQLite和Visual C ++的新手。我究竟做错了什么？还有一种方法可以成功检索SQLite错误消息，这将有助于一堆，因为我无法找到使用Visual c + +的方法。谢谢！

    private:System::Void SaveButton_Click(System::Object^  sender, System::EventArgs^  e) {

        // Convert double to string
        String^ convert;
        std::string MapString[16];

        String^ NameRaw = SaveName->Text;


        std::string nameString = msclr::interop::marshal_as< std::string >(NameRaw);

        // double array to string
        for (int i = 0; i < 15; i++) {
            convert = MeasurementsAndPricesPublic[i].ToString();
            std::string convertString = msclr::interop::marshal_as< std::string >(convert);
            MapString[i] = convertString;
        }

        // SQLITE DATABASE CODE

        sqlite3* db = NULL;
        sqlite3_stmt* query = NULL;


        // created table for the first run
        /*std::string generateTable = "CREATE TABLE PARAMETERS("
            "Name        TEXT      NOT NULL,"
            "PatchFL         TEXT     NOT NULL,"
            "PatchFW           TEXT     NOT NULL,"
            "PatchSL            TEXT     NOT NULL,"
            "PatchSW            TEXT     NOT NULL,"
            "PatchHL            TEXT     NOT NULL,"
            "PatchHW            TEXT     NOT NULL,"
            "AvailableFL            TEXT     NOT NULL,"
            "AvailableFW            TEXT     NOT NULL,"
            "AvailableSL            TEXT     NOT NULL,"
            "AvailableSW            TEXT     NOT NULL,"
            "AvailableHL            TEXT     NOT NULL,"
            "AvailableHW            TEXT     NOT NULL,"
            "AvailableFP            TEXT     NOT NULL,"
            "AvailableSP            TEXT     NOT NULL,"
            "AvailableHP            TEXT      NOT NULL);";*/

        // Table statement I suspect an error here
        std::string sqlstatement = "INSERT INTO PARAMETERS (Name, PatchFL, PatchFW, PatchSL, PatchSW, PatchHL, PatchHW, AvailableFL, AvailableFW, AvailableSL, AvailableSW, AvailableHL, AvailableHW, AvailableFP, AvailableSP, AvailableHP) VALUES ('"
            + nameString + "','"
            + MapString[0] + "','"
            + MapString[1] + "','"
            + MapString[2] + "','"
            + MapString[3] + "','"
            + MapString[4] + "','"
            + MapString[5] + "','"
            + MapString[6] + "','"
            + MapString[7] + "','"
            + MapString[8] + "','"
            + MapString[9] + "','"
            + MapString[10] + "','"
            + MapString[11] + "','"
            + MapString[12] + "','"
            + MapString[13] + "','"
            + MapString[14] + ");";

        // statement for testing did not work either
        const char* sql_insert = "INSERT INTO PARAMETERS (Name, PatchFL, PatchFW, PatchSL, PatchSW, PatchHL, PatchHW, AvailableFL, AvailableFW, AvailableSL, AvailableSW, AvailableHL, AvailableHW, AvailableFP, AvailableSP, AvailableHP)  VALUES (A, A, A, A, A, A, A, A, A, A, A, A, A, A, A, A);";

        // Trying to convert to char with no success
        char * buffer = new char[sqlstatement.length()];
        strcpy(buffer, sqlstatement.c_str());

        int ret = 0;

        do // avoid nested if's
        {
            // initialize engine
            if (SQLITE_OK != (ret = sqlite3_initialize()))
            {
                MessageBox::Show("Failed to initialize library. Error: ", ret.ToString());
                break;
            }
            // open connection to a DB 
            if (SQLITE_OK != (ret = sqlite3_open_v2("parameters.db", &db, SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, NULL)))
            {
                MessageBox::Show("Failed to open connection to database. Error: ", ret.ToString());
                break;
            }

            // executing statement I GET ERROR HERE
            if (SQLITE_OK != (ret = sqlite3_exec(db, buffer, NULL, NULL, errmsg)))
            {
                MessageBox::Show("Failed to prepare the statement. "); //I get this message 

                break;
            }
            MessageBox::Show("Successfully saved parameters");

            //// prepare the statement
            //if (SQLITE_OK != (ret = sqlite3_prepare_v2(db, "SELECT 2012", -1, &query, NULL)))
            //{
            //  MessageBox::Show("Failed to prepare the statement. Error: ", ret.ToString(), sqlite3_errmsg(pDb).ToString());
            //  break;
            //}
            //// step to 1st row of data
            //if (sqlite_row != (ret = sqlite3_step(query))) // see documentation, this can return more values as success
            //{
            //  printf("failed to step: %d, %s\n", ret, sqlite3_errmsg(pdb));
            //  break;
            //}
            //// ... and print the value of column 0 (expect 2012 here)
            //printf("value from sqlite: %s", sqlite3_column_text(query, 0));

        } while (false);
        // cleanup
        if (NULL != query) sqlite3_finalize(query);
        if (NULL != db) sqlite3_close(db);
        sqlite3_shutdown();
    }

Answer 1

您遇到的问题是，您将C ++ / CX UTF-16 Platform :: Strging ^与标准C UTF-8字符串混合在一起。

首先，您必须将String ^转换为char *。请检查以下问题：Convert Platform::String to std::string。

您应该通过致电sqlite3_prepare_v2来准备您的查询：

sqlite3_stmt *query;
const char *tail;
int ser = sqlite3_prepare_v2(m_Db, "INSERT INTO PARAMETERS (a, b, c) VALUES (?, ?, ?)", -1, &result, &tail);
if (ser != SQLITE_OK) {
    const char *err = sqlite3_errmsg(m_Db);
    // report some error
}

准备好语句后，你必须将数据绑定到它并执行它：

sqlite3_bind_text(query, 1, "attempt", 7, SQLITE_STATIC);
sqlite3_bind_text(query, 2, "xxx", 3, SQLITE_STATIC);
sqlite3_bind_text(query, 3, "yyy", 3, SQLITE_STATIC);

if ((ser = sqlite3_step(query)) != SQLITE_DONE) {
    const char *err = sqlite3_errmsg(m_Db);
    // report some error
}

Answer 2

花了5个小时挖掘，解决方案原来是错过了“'” + MapString [14] +“）;”;

SQLite Visual C ++ INSERT INTO＆＃39; table＆＃39;

2 个答案: