Use ODBC connect to MS SQL in C ?

this is a simple example ive knocked up for you, create a simple access or sql server database and create

a system dsn for it in control panel. the open function uses global varaibles etc so you will probably

want to chage this.

/* for db stuff */
#include <windows.h>
#include <sql.h>
#include <sqlext.h>
#include <stdio.h>

HENV henv;
HDBC hdbc;
int dbopen=0;

/* opens a connection using global variables , bad i know */
#define PM_DSN "your_system_dsn"
#define PM_DSN_USER "your_db_username_if_any"
#define PM_DSN_PW "your_password_if_any"

int DBopen(void)
{
   int res=0;
   RETCODE retcode;
   /*allocate the environment handle*/
   if(SQLAllocEnv(&henv)==SQL_SUCCESS)
   {
        /*allocate the connection handle*/
        if(SQLAllocConnect(henv, &hdbc)==SQL_SUCCESS)
        {
             /* Set login timeout to 5 seconds. */
             SQLSetConnectOption(hdbc, SQL_LOGIN_TIMEOUT, 5);
             SQLSetConnectOption(hdbc, SQL_CURSOR_TYPE, SQL_CURSOR_STATIC);
             /* Connect to data source */
             retcode = SQLConnect(hdbc, PM_DSN, SQL_NTS, PM_DSN_USER, SQL_NTS, PM_DSN_PW, SQL_NTS);


             if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO)
             {
                       res=1;
             }
        }
        else
        {
             SQLFreeConnect(hdbc);
        }
   }
   else
   {
        SQLFreeEnv(henv);
   }
   dbopen=res;
   return res;
}

void DBclose(void)
{
   if(dbopen)
   {
        SQLDisconnect(hdbc);
        SQLFreeConnect(hdbc);
        SQLFreeEnv(henv);
        if(DATABASE_NAME)
        {
             free(DATABASE_NAME);
        }
   }
   dbopen=0;
}
int DBexecute(char *sql,HSTMT *hstmt)
{
   int res=0;
   RETCODE retcode;

   if(SQLAllocStmt(hdbc, hstmt)== SQL_SUCCESS)
   {
        retcode=SQLPrepare(*hstmt,sql,strlen(sql));
        if(retcode==SQL_SUCCESS)
        {
             retcode=SQLExecute(*hstmt);
             if(retcode==SQL_SUCCESS)
             {
                  res=1;
             }
        }
   }
   return res;
}

void DBcloseCursor(HSTMT hstmt)
{
   SQLFreeStmt(hstmt, SQL_DROP);
}

void main()
{
   char sql[255];
   HSTMT fstmt;
   long lens;
   RETCODE retcode;
   char name[100];

   DBopen();

   sprintf(sql,"SELECT name FROM users");
   if(DBexecute(sql,&fstmt))
   {      
        SQLBindCol(fstmt,1,SQL_C_CHAR, name,sizeof(name),&lens);
       
        retcode = SQLFetch(fstmt);    
        while(retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO)
        {
             printf("%s\n",name);
             retcode = SQLFetch(fstmt);
        }
        DBcloseCursor(fstmt);
   }
   DBclose();
}