Pro*C Examples

http://www.cs.umbc.edu/help/oracle8.bak/server803/A54661_01/dev.htm#1609

http://www.cs.umbc.edu/help/oracle8.bak/server803/A54661_01/toc.htm

Using C Structures
=================

#include

typedef emptype myemp;

myemp *employee;


ORA_PROC Macro
=================
the precompiler never reads the file.
The following example uses the ORA_PROC macro to exclude the irrelevant.h file:

#ifndef ORA_PROC
#include
#endif


OR

EXEC ORACLE IFNDEF ORA_PROC;

EXEC ORACLE ENDIF;

#define MAX(A,B) ((A) > (B) ? (A) : (B))
VARCHAR name_loc_temp[MAX(ENAME_LEN, LOCATION_LEN)];


You can use the #include, #ifdef and #endif preprocessor directives to conditionally include a file that the precompiler requires. For example:

#ifdef ORACLE_MODE
# include
#else
long SQLCODE;
#endif


TYPE and VAR statements
========================
#define STR_LEN 40
...
typedef char asciiz[STR_LEN];
...
EXEC SQL TYPE asciiz IS STRING(STR_LEN) REFERENCE;
...
EXEC SQL VAR password IS STRING(STR_LEN) REFERENCE;



UNIX systems, you can compile the generated C source file using the command
----------------------------------------------------------------------------------------------------------------------
cc -o progname -I$ORACLE_HOME/sqllib/public ... filename.c ...

switch
---------
ch = getchar();
switch (ch)
{
case 'U': update(); break;
case 'I': insert(); break;
...

Using Numeric Constants in Pro*C/C++
===================================
In Pro*C/C++, normal C scoping rules are used to find and locate the declaration of a numeric constant declaration.

const int g = 30; /* Global declaration to both function_1()
and function_2() */
void function_1()
{
const int a = 10; /* Local declaration only to function_1() */
char x[a];
exec sql select ename into :x from emp where job = 'PRESIDENT';
}

void function_2()
{
const int a = 20; /* Local declaration only to function_2() */
VARCHAR v[a];
exec sql select ename into :v from emp where job = 'PRESIDENT';
}

void main()
{
char m[g]; /* The global g */
exec sql select ename into :m from emp where job = 'PRESIDENT';
}