Yurttas/PL/DBL/oracle/F/03/PC/q11.pc

 1/*  
 2REM
 3REM q11.pc
 4REM
 5REM Find the average hard disk size of a PC for all those
 6REM manufacturers that make printers.
 7REM
 8*/
 9
10#include <stdio.h>
11#include <sqlca.h>
12
13#define UNAME_LEN 32
14#define PWD_LEN   16
15
16VARCHAR username[UNAME_LEN]; /* VARCHAR is an Oracle-supplied struct */
17VARCHAR password[PWD_LEN];   /* varchar can be in lower case also. */
18
19char u_name[UNAME_LEN];
20char pwd[PWD_LEN];
21
22struct {
23  char maker[6];
24  int avghd;
25} product;
26
27void connect_to_oracle();
28void sql_error();
29
30void main(int argc, char* argv[]) {
31  connect_to_oracle();
32
33  EXEC SQL DECLARE c CURSOR FOR
34    SELECT P.maker, AVG(hd)
35    FROM Product P, PC
36    WHERE P.model=PC.model
37      AND P.maker IN (SELECT P.maker
38                      FROM Product P, Printer R
39                      WHERE P.model=R.model)
40    GROUP BY P.maker;
41
42  EXEC SQL OPEN c;
43
44  EXEC SQL WHENEVER NOT FOUND DO BREAK;
45
46  printf("\nmaker\tavghd\n");
47  for(;;) {
48    EXEC SQL FETCH c INTO :product;
49    printf("%s\t%d\n", product.maker,
50                       product.avghd);
51  }
52
53  EXEC SQL CLOSE c;
54
55  EXEC SQL COMMIT WORK RELEASE;
56
57  exit(0);
58}
59
60
61void sql_error(char* msg) {
62  char err_msg[128];
63  int buflen, msglen;
64
65  EXEC SQL WHENEVER SQLERROR CONTINUE;
66
67  printf("%s \n", msg);
68  buflen = sizeof(err_msg);
69  sqlglm(err_msg, &buflen, &msglen);
70  printf("%.*s \n", msglen, err_msg);
71  exit(1);
72}
73
74
75void connect_to_oracle() {
76  /* get your username/passwd from "user_pwd.txt" file */
77
78  FILE *in_file;
79  in_file = fopen("user_pwd.txt", "r");
80  fscanf(in_file, "%s", u_name);
81  fscanf(in_file, "%s", pwd);
82
83  strncpy((char *) username.arr, u_name, UNAME_LEN);
84  username.len = strlen((char *) username.arr);
85
86  strncpy((char *) password.arr, pwd, PWD_LEN);
87  password.len = strlen((char *) password.arr);
88
89  EXEC SQL WHENEVER SQLERROR DO sql_error ("ORACLE error-- ");
90  EXEC SQL CONNECT :username IDENTIFIED BY :password;
91
92  printf("connected to oracle - \n");
93}