SQL Statement in C using a variable in query - c++

Question

I am building a C++ program that accesss an SQL database. I am able to connect and return values for the following statment:
retcode = SQLExecDirect(hstmt, (SQLWCHAR*)L"SELECT Beta FROM Equity WHERE Ticker = 'AAPL'", SQL_NTS);
However, I would like to be able to replace 'AAPL' with the string 'ticker', which can be defined using cin>>.
Is there any way to do this?
Thanks for the help, the entire code is below:
#include "stdafx.h"
#include <iostream>
#include <windows.h>
#include <sql.h>
#include <sqltypes.h>
#include <sqlext.h>
#include <string>
using namespace std;
int main(){
SQLHENV henv;
SQLHDBC hdbc;
SQLHSTMT hstmt;
SQLRETURN retcode;
SQLWCHAR OutConnStr[255];
SQLSMALLINT OutConnStrLen;
// Allocate environment handle
retcode = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &henv);
// Set the ODBC version environment attribute
if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {
retcode = SQLSetEnvAttr(henv, SQL_ATTR_ODBC_VERSION, (void*)SQL_OV_ODBC3, 0);
// Allocate connection handle
if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {
retcode = SQLAllocHandle(SQL_HANDLE_DBC, henv, &hdbc);
// Set login timeout to 5 seconds
if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {
SQLSetConnectAttr(hdbc, SQL_LOGIN_TIMEOUT, (SQLPOINTER)5, 0);
// Connect to data source
retcode = SQLDriverConnect(
hdbc,
0,
(SQLWCHAR*)L"DSN=Phoenix;SERVER=XXX;UID=XXX;PWD=XXX;DRIVER=MySQL Server;",
_countof(L"DSN=Phoenix;SERVER=XXX;UID=XXX;PWD=XXX;DRIVER=MySQL Server;"),
OutConnStr,
255,
&OutConnStrLen,
SQL_DRIVER_COMPLETE );
// Allocate statement handle
if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {
retcode = SQLAllocHandle(SQL_HANDLE_STMT, hdbc, &hstmt);
// Process data
string ticker;
cout << " Enter Ticker: "; //Prompt Ticker
cin >> ticker; //Stores Ticker
//retcode = SQLExecDirect(hstmt, (SQLWCHAR*)L"SELECT Beta FROM Equity WHERE Ticker = 'AAPL'", SQL_NTS);
retcode = SQLExecDirect(hstmt, (SQLWCHAR*)L"SELECT Beta FROM Equity WHERE Ticker = ticker", SQL_NTS);
if (retcode == SQL_SUCCESS) {
SQLINTEGER cbTestStr, iCount = 1;
SQLFLOAT dTestFloat;
SQLCHAR beta[200];
while (TRUE) {
retcode = SQLFetch(hstmt);
if (retcode == SQL_ERROR || retcode == SQL_SUCCESS_WITH_INFO) {
cout<<"An error occurred";
}
if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO){
SQLGetData(hstmt, 1, SQL_C_CHAR, beta, 200, &cbTestStr);
/* Print the row of data */
cout<<"Beta for "<< ticker << " = " << beta <<endl;
double bi;
cin >> bi;
} else {
break;
}
}
}else{
cout<<"Query execution error."<<endl;
}
SQLFreeHandle(SQL_HANDLE_STMT, hstmt);
SQLDisconnect(hdbc);
}else{
cout<<"Connection error"<<endl;
}
SQLFreeHandle(SQL_HANDLE_DBC, hdbc);
}
}
SQLFreeHandle(SQL_HANDLE_ENV, henv);
}
system("pause");
return 0;
}

Answer 1

Have you tried something like after your cin >> ticker; line.
string sql;
sql = "SELECT Beta FROM Equity WHERE Ticker='";
strcat (sql,ticker);
strcat (sql, "'");
Then use the sql string in SQLExecDirect line
Replace the statement text with sql.
Sorry my c syntax is rusty. The point is to retrieve ticker value and concatenate that to the sql string while surrounding the input (ticker) with single quotes. Then use this as your execution statement.
Hope it works.