/* a C program with embedded SQL statements
   file: first.pgc   Preprocess it with ecpg
     ecpg  first.pgc
-- this should give the C file  first.c, which can be compiled.
	   -- link with file libecpg when linking. All needed files are 
		in their expected locations on all j118 machines.
	   	(use -lecpg), so:
     gcc first.c -lecpg 
Lin Jensen

PROBLEMS: '-' in cs-linux
	null values can cause trouble, see manual section 30.6.4
	
	char and "varchar" are not null terminated, text is,
	so use a type cast in SQL, and allow one extra byte!
****************************/
#define NO_MORE_TUPLES !(strcmp(sqlca.sqlstate,"02000"))
			/* This is the SQL standard test */
#include <stdlib.h>

int main (int argc, char* argv[]) {

	/* Declare variables here that we want to refer to in SQL */
EXEC SQL BEGIN DECLARE SECTION;
   const char *target = "timetable@cs-linux";
   /* need string because ecpg dislikes - in cs-linux*/
   char course[10];
   varchar title[26];
   char    prof[16];
   char    room[7];
   char    email[13];
   int     email_ind;	/* will be negative if value is null */
   char    who[12];
EXEC SQL END DECLARE SECTION;

/* declare regular C variables here */
   int count;

EXEC SQL WHENEVER SQLERROR SQLPRINT;      /* ask for error messages */
EXEC SQL WHENEVER SQLWARNING SQLPRINT;

EXEC SQL CONNECT TO :target USER mickey/MoUsE;

/* Let's do a query now */
    if (argc<2)
    { printf ("Usage: %s ROOM\n", argv[0]);
      exit(1);
    }
	strcpy(who, argv[1]);		/* some room number from command line */

  EXEC SQL DECLARE rowCurs CURSOR FOR
    SELECT course, title, prof::TEXT, room::text, email::text
    FROM  courses left join profs on (prof=pname)
    WHERE room = :who;
  EXEC SQL OPEN rowCurs;

  printf ("==== LIST of COURSES for room: %s =====\n",who);
  count = 0;
  while(1) {
     EXEC SQL FETCH rowCurs INTO :course, :title, :prof, :room,
     	 :email :email_ind;	/* could be null, note lack of comma */
     if (NO_MORE_TUPLES) break;
     course[9] = '\0';             /* null terminate char strings */
     title.arr[title.len] = '\0';  /* null terminate varchar string */
     if (email_ind < 0) strcpy(email,"(null)");
     printf ("%s %-25s %s %s   email: %s\n",course, title.arr, room, prof, email);
     			/* we want title left justified (-) and padded anyway.
			   note the effect of variable length on prof */
     count++;
  }
EXEC SQL CLOSE rowCurs; /* finished with this cursor     */
EXEC SQL COMMIT;	/* successful end of transaction */

  printf ("%d rows selected.\n", count);

EXEC SQL DISCONNECT;

return 0;
}  /* end main*/