Re: PUBLIC: Calling PL/SQL stored procedure from C

From: Thomas Kyte <tkyte_at_us.oracle.com>
Date: Wed, 30 Dec 1998 14:42:07 GMT
Message-ID: <368b3ba1.6043429@192.86.155.100>

A copy of this was sent to Oliver Muthig <oliver.muthig_at_ubs.com> (if that email address didn't require changing) On Tue, 29 Dec 1998 12:01:52 +0100, you wrote:

>Hi,
>
>how could I call the stored procedure from C and process the results?
>Hostvariables ? Host arrays ? Which C datatypes should I use ?
>
>I read the Oracle Documentation but there are only trivial examples
>using simple build in datatypes.
>

With 7.2 on up of the database you have cursor variables. Cursor variables are cursors opened by a pl/sql routine and fetched from by another application or pl/sql routine (in 7.3 pl/sql routines can fetch from cursor variables as well as open them). The cursor variables are opened with the privelegs of the owner of the procedure and behave just like they were completely contained within the pl/sql routine. It uses the inputs to decide what database it will run a query on.

Here is an example:

create or replace package types
as

    type cursorType is ref cursor;
end;
/  

create or replace function sp_ListEmp return types.cursortype as

    l_cursor types.cursorType;
begin

    open l_cursor for select ename, empno from emp order by ename;  

    return l_cursor;
end;
/    

REM SQL*Plus commands to use a cursor variable  

variable c refcursor
exec :c := sp_ListEmp
print c

---

and the Pro*c to use this would look like:

static void process()
{
EXEC SQL BEGIN DECLARE SECTION;
    SQL_CURSOR my_cursor;

    VARCHAR     ename[40];
    int         empno;

EXEC SQL END DECLARE SECTION;       EXEC SQL WHENEVER SQLERROR DO sqlerror_hard();  

    EXEC SQL ALLOCATE :my_cursor;  

    EXEC SQL EXECUTE BEGIN
        :my_cursor := sp_listEmp;
    END; END-EXEC;       for( ;; )
    {

        EXEC SQL WHENEVER NOTFOUND DO break;
        EXEC SQL FETCH :my_cursor INTO :ename, empno;
 
        printf( "'%.*s', %d\n", ename.len, ename.arr, empno );

    }
    EXEC SQL CLOSE :my_cursor;
}

>CREATE OR REPLACE PACKAGE HS7_PG_AUTOMATIC_SELECTS AS
>
>TYPE DATE_ARRAY IS TABLE OF DATE INDEX BY BINARY_INTEGER;
>TYPE LONG_ARRAY IS TABLE OF LONG INDEX BY BINARY_INTEGER;
>TYPE NUMBER_ARRAY IS TABLE OF NUMBER INDEX BY BINARY_INTEGER;
>TYPE VARCHAR2_ARRAY IS TABLE OF VARCHAR2(255) INDEX BY BINARY_INTEGER;
>...
>FUNCTION SELECT_SYSINFOLIST_ARRAY (
> SESSIONID IN NUMBER,
> ROWS IN OUT BINARY_INTEGER,
> SYSID_ARRAY OUT NUMBER_ARRAY,
> SYSTEM_ARRAY OUT VARCHAR2_ARRAY,
> COMPONENT_ARRAY OUT VARCHAR2_ARRAY,
> TIMESTAMP_ARRAY OUT DATE_ARRAY,
> AGE_ARRAY OUT VARCHAR2_ARRAY,
> VALUE_ARRAY OUT VARCHAR2_ARRAY,
> WHERE_CLAUSE IN VARCHAR2 DEFAULT '') RETURN VARCHAR2;
>...
>
>Thanks for your help.
>
>Oliver
>
 

Thomas Kyte
tkyte_at_us.oracle.com
Oracle Service Industries
Reston, VA USA

--
http://govt.us.oracle.com/ -- downloadable utilities  

---

Opinions are mine and do not necessarily reflect those of Oracle Corporation  

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