Yurttas/PL/DBL/oracle/F/03/PC/q05.pc

 1/*  
 2REM
 3REM q05.pc
 4REM
 5REM Find those manufacturers that sell Laptops, but not PC's.
 6REM
 7*/
 8
 9#include <stdio.h>
10#include <sqlca.h>
11
12#define UNAME_LEN 32
13#define PWD_LEN   16
14
15VARCHAR username[UNAME_LEN]; /* VARCHAR is an Oracle-supplied struct */
16VARCHAR password[PWD_LEN];   /* varchar can be in lower case also. */
17
18char u_name[UNAME_LEN];
19char pwd[PWD_LEN];
20
21struct {
22  char maker[6];
23} product;
24
25void connect_to_oracle();
26void sql_error();
27
28void main(int argc, char* argv[]) {
29  connect_to_oracle();
30
31  EXEC SQL DECLARE c CURSOR FOR
32    (SELECT P.maker
33     FROM Product P, Laptop L
34     WHERE P.model=L.model)
35    MINUS
36    (SELECT P.maker
37     FROM Product P, PC
38     WHERE P.model=PC.model);
39
40  EXEC SQL OPEN c;
41
42  EXEC SQL WHENEVER NOT FOUND DO BREAK;
43
44  printf("\nmaker\n");
45  for(;;) {
46    EXEC SQL FETCH c INTO :product;
47    printf("%s\n", product.maker);
48  }
49
50  EXEC SQL CLOSE c;
51
52  EXEC SQL COMMIT WORK RELEASE;
53
54  exit(0);
55}
56
57
58void sql_error(char* msg) {
59  char err_msg[128];
60  int buflen, msglen;
61
62  EXEC SQL WHENEVER SQLERROR CONTINUE;
63
64  printf("%s \n", msg);
65  buflen = sizeof(err_msg);
66  sqlglm(err_msg, &buflen, &msglen);
67  printf("%.*s \n", msglen, err_msg);
68  exit(1);
69}
70
71
72void connect_to_oracle() {
73  /* get your username/passwd from "user_pwd.txt" file */
74
75  FILE *in_file;
76  in_file = fopen("user_pwd.txt", "r");
77  fscanf(in_file, "%s", u_name);
78  fscanf(in_file, "%s", pwd);
79
80  strncpy((char *) username.arr, u_name, UNAME_LEN);
81  username.len = strlen((char *) username.arr);
82
83  strncpy((char *) password.arr, pwd, PWD_LEN);
84  password.len = strlen((char *) password.arr);
85
86  EXEC SQL WHENEVER SQLERROR DO sql_error ("ORACLE error-- ");
87  EXEC SQL CONNECT :username IDENTIFIED BY :password;
88
89  printf("connected to oracle - \n");
90}