SQL Server Connection c++ - c++

Question

I'm having trouble connecting to my local SQL Server Express DB. I'm fairly new to c++ and wanted to try messing around with "simple" server connections to mess around with dbs. But I have two main errors I keep getting and haven't figured out I believe everything in the backend is setup correctly (ie. server users/logins & accessibility) heres the code I have atm:
#include "pch.h"
#include <iostream>
#include <windows.h>
#include <sqlext.h>
#include <sqltypes.h>
#include <sql.h>
using namespace std;
void showSQLError(SQLCHAR desc[1024], unsigned int handleType, const SQLHANDLE& handle)
{
SQLCHAR SQLState[1024];
SQLCHAR message[1024];
if (SQL_SUCCESS == SQLGetDiagRec(handleType, handle, 1, SQLState, NULL, message, 1024, NULL))
// Returns the current values of multiple fields of a diagnostic record that contains error, warning, and status information
cout << "At Point:" << desc << endl;
cout << "SQL driver message: " << message << "\nSQL state: " << SQLState << "." << endl;
}
int main()
{
cout << "Hello world" << endl;
SQLHANDLE SQLEnvHandle = NULL;
SQLHANDLE SQLConnectionHandle = NULL;
SQLHANDLE SQLStatementHandle = NULL;
SQLRETURN retCode = 0;
//desc
SQLCHAR noData[1024] = "SQL_NO_DATA\n";
SQLCHAR invalidHandle[1024] = "SQL_INVALID_HANDLE\n";
SQLCHAR error[1024] = "SQL_ERROR\n";
SQLCHAR success[1024] = "Connection succesful";
char SQLQuery[] = "SELECT * FROM roster";
do {
if (SQL_SUCCESS != SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &SQLEnvHandle))
// Allocates the environment
break;
if (SQL_SUCCESS != SQLSetEnvAttr(SQLEnvHandle, SQL_ATTR_ODBC_VERSION, (SQLPOINTER)SQL_OV_ODBC3, 0))
// Sets attributes that govern aspects of environments
break;
if (SQL_SUCCESS != SQLAllocHandle(SQL_HANDLE_DBC, SQLEnvHandle, &SQLConnectionHandle))
// Allocates the connection
break;
if (SQL_SUCCESS != SQLSetConnectAttr(SQLConnectionHandle, SQL_LOGIN_TIMEOUT, (SQLPOINTER)5, 0))
// Sets attributes that govern aspects of connections
break;
SQLCHAR retConString[1024]; // Conection string
switch (SQLDriverConnect(SQLConnectionHandle, NULL, (SQLCHAR*)"DRIVER={SQL Server Native Client 11.0}; SERVER=MYPC\SQLEXPRESS, 1433; DATABASE=MYdb; UID=myID; PWD=myPWD ", SQL_NTS, retConString, 1024, NULL, SQL_DRIVER_NOPROMPT)) {
// Establishes connections to a driver and a data source
case SQL_SUCCESS:
break;
case SQL_SUCCESS_WITH_INFO:
break;
case SQL_NO_DATA_FOUND:
showSQLError(noData , SQL_HANDLE_DBC, SQLConnectionHandle);
retCode = -1;
break;
case SQL_INVALID_HANDLE:
showSQLError(invalidHandle, SQL_HANDLE_DBC, SQLConnectionHandle);
retCode = -1;
break;
case SQL_ERROR:
showSQLError(error, SQL_HANDLE_DBC, SQLConnectionHandle);
retCode = -1;
break;
default:
break;
}
if (retCode == -1)
break;
if (SQL_SUCCESS != SQLAllocHandle(SQL_HANDLE_STMT, SQLConnectionHandle, &SQLStatementHandle))
// Allocates the statement
break;
if (SQL_SUCCESS != SQLExecDirect(SQLStatementHandle, (SQLCHAR*)SQLQuery, SQL_NTS)) {
// Executes a preparable statement
showSQLError(success, SQL_HANDLE_STMT, SQLStatementHandle);
break;
}
else {
char name[256];
int age;
while (SQLFetch(SQLStatementHandle) == SQL_SUCCESS) {
// Fetches the next rowset of data from the result
SQLGetData(SQLStatementHandle, 1, SQL_C_DEFAULT, &name, sizeof(name), NULL);
SQLGetData(SQLStatementHandle, 2, SQL_C_DEFAULT, &age, sizeof(age), NULL);
// Retrieves data for a single column in the result set
cout << name << " " << age << endl;
}
}
} while (FALSE);
SQLFreeHandle(SQL_HANDLE_STMT, SQLStatementHandle);
SQLDisconnect(SQLConnectionHandle);
SQLFreeHandle(SQL_HANDLE_DBC, SQLConnectionHandle);
SQLFreeHandle(SQL_HANDLE_ENV, SQLEnvHandle);
// Frees the resources and disconnects
getchar();
}
so my initial error with the above code is:
At Point:SQL_ERROR
SQL driver message: [Microsoft][SQL Server Native Client 11.0]TCP Provider: No such host is known.
SQL state: 08001.
And if I change my connection string to:
SQLDriverConnect(SQLConnectionHandle, NULL, (SQLCHAR*)"DRIVER={SQL Server
Native Client 11.0}; SERVER=MYPC\\SQLEXPRESS, 1433; DATABASE=MYdb;
UID=myID; PWD=myPWD ", SQL_NTS, retConString, 1024, NULL, SQL_DRIVER_NOPROMPT))
NOTE: The added '\' in the SERVER string
I get:
At Point:SQL_ERROR
SQL driver message: [Microsoft][SQL Server Native Client 11.0]TCP Provider: No connection could be made because the target machine actively refused it.
SQL state: 08001.
I beleive the \ is correct but unclear as to why it would be refused. I have setup all the permissions and accounts for the server correctly (assumingly) unless my approach is just straight up incorrect. Where/ would my local server be refusing my connection attempt?

Answer 1

I have never seen an instance name like "MYPC\SQLEXPRESS, 14.0". It should almost certainly be just "MYPC\SQLEXPRESS", and if it actually is "MYPC\SQLEXPRESS, 14.0" it needs to be contained in {} the way the driver name is.
I suggest you use the "sqlcmd -L" command (install it from https://www.microsoft.com/en-us/download/details.aspx?id=53591 if you don't already have it) and use one of the instance names that returns.
The benefit of sqlcmd over other instance listing methods I'm aware of is that sqlcmd uses ODBC and thus you will get a name that the SQL Server ODBC driver is ready to use.