insert into mysql c++

#include <mysql.h>
#include <iostream>
#include <iomanip>
#include <fstream>

using namespace std;

MYSQL *conn, mysql;
MYSQL_RES *res;
MYSQL_ROW row;

int query_state;

int main()
{
   const char *server="students";
   const char *user="*****";
   const char *password="********";
   const char *database="*****";

   mysql_init(&mysql);
   conn=mysql_real_connect(&mysql, server, user, password, database, 0, 0, 0);
   if(conn==NULL)
   {
       cout<<mysql_error(&mysql)<<endl<<endl;
      return 1;
   }
   query_state=mysql_query(conn, "select * from Instrument");
   if(query_state!=0)
   {
      cout<<mysql_error(conn)<<endl<<endl;
      return 1;
   }
   res=mysql_store_result(conn);
   cout<<"MySQL Tables in mysql database."<<endl<<endl;
   while((row=mysql_fetch_row(res))!=NULL)
   {
      cout<<left;
      cout<<setw(18)<<row[0]
          <<setw(18)<<row[1]
          <<setw(18)<<row[2]
          <<setw(18)<<row[3]<<endl;
   }
   cout<<endl<<endl;
   ifstream infile;
   infile.open("Instrument.txt");
   if(infile.fail())
   {
      cout<<"ERROR. Could not open file!"<<endl;
      return 1;
   }
   infile.seekg(0, infile.end);
   int len=infile.tellg();
   infile.seekg(0, infile.beg);
   string instnum, insttype, maker, year, plID, name, salary, startdate;
   string rating;
   string instrument="INSERT INTO Instrument (InstrumentID, InstrumentType, MakerName, YearMade) VALUES ( '"+instnum+"', '"+insttype+"', '"+maker+"', '"+year+"')";
   string player="INSERT INTO Player (PlayerID, Name, Salary, StartDate) values (plID, name, salary, startdate)";
   string plays="INSERT INTO Plays (InstrumentID, PlayerID, Rating) values (instnum, plID, rating)";
//   mysql_query(conn, "DELETE FROM Instrument WHERE MakerName='maker'");
   while(infile)
   {
      infile>>instnum;
      cout<<instnum<<endl;
      infile>>insttype;
      cout<<insttype<<endl;
      infile>>maker;
      cout<<maker<<endl;
      infile>>year;
      cout<<year<<endl;
      query_state=mysql_query(conn, instrument.c_str());
   }

   if(query_state!=0)
   {
      cout<<mysql_error(conn)<<endl<<endl;
      return 1;
   }
   cout<<endl<<endl;

   mysql_free_result(res);
   mysql_close(conn);

   return 0;