Templates and Pro*C/C++ (maybe EXEC SQL TYPE?)

From: Alex Vinokur <alexander.vinokur_at_telrad.co.il>
Date: Mon, 11 Oct 1999 08:59:18 GMT
Message-ID: <7ts8t1$fp0$1_at_nnrp1.deja.com>

Hi,

I need the following function updateRow() in Pro*C/C++.

//-------------------------------------

template <class T1, class T2>
bool updateRow (

                        const string&   tableName_i,
                        const string&   keyColName_i,
                        const T1&       keyColValue_i,
                        const string&   dataColName_i,
                        const T2&       dataColValue_i
                        );
//-------------------------------------
I want updateRow()
        to update column dataColName_i (new value is dataColValue_i)
        if column keyColValue_i is equal keyColValue_i;

Notes. Tables contain several columns of different types
       (NUMBER, VARCHAR2, CHAR).
       I don't know beforehand what keyColName_i and dataColName_i
       will be checked and updated in my main program.

Here is examples of desirable calling updateRow() :

1. updateRow ("AAA", "emp_no", 127, "salary", 7925);
2. updateRow ("BBB", "weight", 101, "dep_name", "Testing");
3. updateRow ("AAA", "job", "analyst", dep_no, 3112);
4. updateRow ("AAA", "location", "boston", "job", "manager");

Questions.
A) How can we write (in Pro*C/C++) template function

   something like code below?
   The problem is how to define host variables    from template variables.
B) Can we use another Pro*C/C++ features

   to gain our goal not using template function    (For instance, EXEC SQL TYPE ...)?

        Thanks in advance,
        Alex



//#########################################################
//------------------- Pro*C/C++ code : BEGIN --------------



#include <string>

#include <sqlca.h>
#include <oraca.h>

template <class T1, class T2>
bool updateRow (

                        const string&   tableName_i,
                        const string&   keyColName_i,
                        const T1&       keyColValue_i,
                        const string&   dataColName_i,
                        const T2&       dataColValue_i
                        )

{

string tmp_str;

#define KEY_COL_VALUE_HOST keyColValue_host;
#define DATA_COL_VALUE_HOST dataColValue_host;

//-----------------------------------------
EXEC SQL BEGIN DECLARE SECTION;
T1      KEY_COL_VALUE_HOST      = keyColValue_i; // ???
T2      DATA_COL_VALUE_HOST     = keyColValue_i; // ???

// By the way : can we use string (STL-string) as host variable? EXEC SQL END DECLARE SECTION;

//-----------------------------------------

        //=========================================
        EXEC SQL WHENEVER SQLERROR GOTO case_update_error;
        //-----------------------------------------

        //-----------------------------------------
        tmp_str = "EXEC SQL UPDATE ";
        tmp_str += tableName_i;
        tmp_str += " SET ";
        tmp_str += dataColName_i;
        tmp_str += " = :";
        tmp_str += KEY_COL_VALUE_HOST;
        tmp_str += " WHERE ";
        tmp_str += dataColName_i;
        tmp_str += " = :";
        tmp_str += KEY_COL_VALUE_HOST;
        //-----------------------------------------

//-----------------------------------------

EXEC SQL BEGIN DECLARE SECTION;
const char* execute_line__host = ((const char*)tmp_str); EXEC SQL END DECLARE SECTION;

//-----------------------------------------

        //-----------------------------------------
        EXEC SQL EXECUTE IMMEDIATE : execute_line__host;
        return true;
        //-----------------------------------------

        //=====================================
        case_update_error:
                EXEC SQL WHENEVER SQLERROR DO sql_bug();
                sql_error_message ();
                return false;
        //=====================================

} // bool       updateRow ()

//------------------- Pro*C/C++ code : END ----------------



//#########################################################
//------------------- System ------------------------------

=== Oracle 8.0.5

=== Pro*C/C++ : Release 8.0.5.0.0
=== SunOS 5.6

//---------------------------------------------------------

//#########################################################

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Before you buy. Received on Mon Oct 11 1999 - 10:59:18 CEST