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Oracle® Objects for OLE C++ Class Library Developer's Guide 10g Release 2 (10.2) Part Number B14308-01 |
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# operator double

Applies To

OField

OParameter

OValue

Description

This method returns the object's value as a double.

Usage

operator double() const

Remarks

This method hands the value of the object back to the caller as a double. If the object's current value is not a double, the method attempts to convert the value. This can fail., resulting in a return of the value 0.0.

Return Value

The value of the field as a double; 0.0 on failure.

Example

Sum all the salaries of employees:

    // open the employee database
    ODatabase odb("ExampleDB", "scott", "tiger");

    // open a dynaset on the employee's table
    ODynaset odyn(odb, "select sal, comm from employees");

    // get a field on the salary for speed
    OField salf = odyn.GetField("sal");
    /*

    By using the = operator in the declaration of salf we are invoking the copy
    constructor. It is copying the temporary object that is returned by the GetField
    method.
    */

    // sum the salaries
    double sumsal = 0.0;
    odyn.MoveFirst();
    while (!odyn.IsEOF())
    {
        sumsal += (double) salf;
        odyn.MoveNext();
    }

    // of course, we could have done the same thing (faster) with:
    ODatabase odb("ExampleDB", "scott", "tiger");
    ODynaset odyn(odb, "select sum(sal) from employees");
    odyn.GetFieldValue(0, &sumsal);
    // the server is good at that kind of bulk calculation