3.下面從Pro*C的一個簡單程序入手:
#include <iostream>
using namespace std;
EXEC SQL INCLUDE SQLCA;

EXEC SQL BEGIN DECLARE SECTION;
char username[30];
char password[20];
char last_name[30];
EXEC SQL END DECLARE SECTION;

void sqlerror();
main()
{
 EXEC SQL WHENEVER SQLERROR
  DO sqlerror();
 strcpy(username,"langzi");
 strcpy(password,"langzi");
 EXEC SQL CONNECT:username
 IDENTIFIED BY:password;
 EXEC SQL select LAST_NAME
    into:last_name from S_EMP where id=2;
    printf("\nID=2,last_name=%s\n",last_name);
}
void sqlerror()
{
 EXEC SQL WHENEVER SQLERROR
 CONTINUE;
  printf("\n=>oracle error detected:\n");
  printf("%.60s\n",sqlca.sqlerrm.sqlerrmc);
 EXEC SQL ROLLBACK WORK RELEASE;
 exit(1);
}
4.從上面的程序簡要看一下其結構:
    (1)include頭文件(包括c/c++和Pro*C/C++)
    (2)定義變量
    (3)定義函數
    (4)寫主方法main
       聯接數據庫:connect
       SQL操作語句:EXEC SQL..........;
       exception
       斷開聯接,釋放連接:EXEC SQL COMMIT/ROLLBACK WORK RELEASE