Just Logic/SQL Relational Database Management System

C program example using the Just Logic/SQL C Precompiler

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(By the way, the term "precompiler" that is used in database terminology has no relation with C precompilers that are part of C compilers and that handle the "#include", "#if", etc. in C programs.)

Here is a short example of program code.

Let's suppose that we have a table named "customer":

Here is a C function that displays the customer table, ordered by name:

void display_customer ()
{
   /* declare a cursor, and it's SQL statement */
   EXEC SQL DECLARE  customer_cursor
            CURSOR FOR
            select   customer_id, name, address
            from     customer
            order by customer_id;

   /* print the title */
   printf ("name:                id:        address:\n");

   /* tell the precompiler what to do in case of exception */
   EXEC SQL whenever sqlerror   goto end;
   EXEC SQL whenever sqlwarning continue;
   EXEC SQL whenever not found  goto end;

   /* open the cursor */
   EXEC SQL OPEN customer_cursor;

   for (;;)
   {  /* fetch next row */
      EXEC SQL fetch customer_cursor into :customer_name,
                                          :customer_id,
                                          :customer_address;
      /* print name, id and address */
      printf ( "%-20.20s", customer_name);
      printf (" %-10.10s", customer_id);
      printf (" %-20.20s\n", customer_address);
   }

end:
   EXEC SQL whenever sqlerror continue;

   /* close the cursor */
   EXEC SQL close customer_name_list_cursor;
}

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Last modification: 4/96