/****************************************************************/
/* Dynamic SQL -- prepare and execute (Section 3.10.2)          */
/* Chapter 3; Oracle Programming -- A Primer                    */
/*            by R. Sunderraman                                 */
/****************************************************************/

#include <stdio.h>
#define FALSE 0
#define TRUE 1

EXEC SQL begin declare section;
  char sql_stmt[256];
  int num;
  varchar userid[10], password[15];
EXEC SQL end declare section;

EXEC SQL include sqlca;
void sql_error(char msg[]);

main () {
  int loginok=FALSE,logintries=0;

  do {
    printf("Enter your USERID: ");
    scanf("%s", userid.arr);
    userid.len = strlen(userid.arr);
    printf("Enter your PASSWORD: ");
    system("stty -echo");
    scanf("%s", password.arr);
    password.len = strlen(password.arr); 
    system("stty echo");
    printf("\n");
    EXEC SQL connect :userid identified by :password;
    if (sqlca.sqlcode == 0) 
      loginok = TRUE;
    else 
      printf("Connect Failed\n");
    logintries++;
  } while ((!loginok) && (logintries <3));
  if ((logintries == 3) && (!loginok)) {
    printf("Too many tries at signing on!\n");
    exit(0);      
  }

  strcpy(sql_stmt,"update employees set hdate=sysdate where eno = :n");

  EXEC SQL set transaction read write;
  EXEC SQL prepare s from :sql_stmt;

  do {
    printf("Enter eno to update (0 to stop):>");
    scanf("%d",&num);
    if (num > 0) {
      EXEC SQL execute s using :num;
      if (sqlca.sqlcode < 0)  {
        sql_error("Problem\n");
        exit(1);
      }
      EXEC SQL commit;
    }
  } while (num > 0);

  EXEC SQL commit release;
  exit(0);
}

void sql_error(char msg[]) {
    char err_msg[128];
    size_t buf_len, msg_len;

    EXEC SQL whenever sqlerror continue;

    printf("\n%s\n", msg);
    buf_len = sizeof (err_msg);
    sqlglm(err_msg, &buf_len, &msg_len);
    printf("%.*s\n", msg_len, err_msg);

    EXEC SQL rollback release;
    exit(1);
}