[英]sqlbindparameter not used for all parameters - mysql & C++
我在MySQL中定义了下表
INSERT INTO routemaster_log (`EntryDateTime`,`Entry`,`Message`,`EntryType`) VALUES (?,?,?,?);
CREATE TABLE `routemaster_log` (
`EntryDateTime` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
`Entry` varchar(127) NOT NULL,
`Message` int(11) NOT NULL DEFAULT '0',
`EntryType` varchar(20) NOT NULL DEFAULT 'INFORMATION'
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
和以下C ++代码向其中写入记录
void LogEntries::Insert(string_t LogText, string_t LogType, int MessageNumber)
{
SQLHANDLE hEnv;
SQLRETURN retCode;
SQLCHAR* query;
SQLINTEGER textLength = SQL_NTS;
// now set the text to be written to char *
char* logText = from_string_t(LogText);
char* logType = from_string_t(LogType);
std::string SQLQuery("INSERT INTO routemaster_log (`Entry`,`Message`,`EntryType`) VALUES (?,?,?)");
query = (SQLCHAR *)SQLQuery.c_str();
.
.
.
// log Text
retCode = SQLBindParameter(hStmnt, 1, SQL_PARAM_INPUT,
SQL_C_CHAR, SQL_CHAR, 0, 0,
logText, sizeof(logText), &textLength);
if (retCode != SQL_SUCCESS && retCode != SQL_SUCCESS_WITH_INFO) {
std::cout << "SQL Insert failed binding parameters (LogText)" << std::endl;
}
// Message Number
retCode = SQLBindParameter(hStmnt, 1, SQL_PARAM_INPUT, SQL_C_LONG, SQL_INTEGER, 0, 0, &MessageNumber, 0, NULL);
if (retCode != SQL_SUCCESS && retCode != SQL_SUCCESS_WITH_INFO) {
std::cout << "SQL Insert failed binding parameters (Message Number)" << std::endl;
}
// Log Type
retCode = SQLBindParameter(hStmnt, 1, SQL_PARAM_INPUT,
SQL_C_CHAR, SQL_CHAR, 0, 0,
logType, sizeof(logType), &textLength);
if (retCode != SQL_SUCCESS && retCode != SQL_SUCCESS_WITH_INFO) {
std::cout << "SQL Insert failed binding parameters (LogType)" << std::endl;
}
retCode = SQLExecDirectA(hStmnt, query, SQL_NTS);
if (retCode != SQL_SUCCESS && retCode != SQL_SUCCESS_WITH_INFO)
{
SQLWCHAR Msg[255], SqlState[6];
SQLINTEGER NativeError;
SQLRETURN ret2;
SQLSMALLINT i, MsgLen;
i = 1;
while ((ret2 = SQLGetDiagRec(SQL_HANDLE_STMT, hStmnt, i, SqlState, &NativeError,
Msg, sizeof(Msg), &MsgLen)) != SQL_NO_DATA) {
std::cout << Msg << std::endl;
i++;
}
std::cout << "SQL Insert failed writing data to database." << std::endl;
}
}
一切正常,直到SQLExecDirectA失败,并且SQLBindParameter没有用于所有参数错误(在以下while循环中获取)。
如果绑定的参数数量与“?”数量不同,我会期望这一点 在查询中,但它们是相同的。
有人对哪里出了问题提出了建议吗?
问题中的代码实际上有两个问题。
a)对SQLBindParameter的调用先于对SQLPrepareA的调用
b)在对SQLBindParameter的调用中,第二个Parameter给出了参数的位置
修改后的代码-如下所示;
// log Text
retCode = SQLBindParameter(hStmnt, 1, SQL_PARAM_INPUT,
SQL_C_CHAR, SQL_CHAR, 0, 0,
logText, sizeof(logText), &textLength);
if (retCode != SQL_SUCCESS && retCode != SQL_SUCCESS_WITH_INFO) {
std::cout << "SQL Insert failed binding parameters (LogText)" << std::endl;
}
// Message Number
retCode = SQLBindParameter(hStmnt, 2, SQL_PARAM_INPUT, SQL_C_LONG, SQL_INTEGER, 0, 0, &MsgNumber, 0, NULL);
if (retCode != SQL_SUCCESS && retCode != SQL_SUCCESS_WITH_INFO) {
std::cout << "SQL Insert failed binding parameters (Message Number)" << std::endl;
}
// Log Type
retCode = SQLBindParameter(hStmnt, 3, SQL_PARAM_INPUT,
SQL_C_CHAR, SQL_CHAR, 0, 0,
logType, sizeof(logType), &textLength);
if (retCode != SQL_SUCCESS && retCode != SQL_SUCCESS_WITH_INFO) {
std::cout << "SQL Insert failed binding parameters (LogType)" << std::endl;
}
retCode = SQLPrepareA(hStmnt, query, SQL_NTS);
if (retCode != SQL_SUCCESS && retCode != SQL_SUCCESS_WITH_INFO) {
std::cout << "SQL Insert failed preparing statement" << std::endl;
}
retCode = SQLExecDirectA(hStmnt, query, SQL_NTS);
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