Thread: Need help comparing db field values in c++

It depends on how you are accessing the db.

If for instance you are using ADO, the return is a VARIANT so it pretty much depends on how you are linking to the db

If you write out the values of Field1 and Field2 are they what you expect them to be, (in other words, are you sure you are getting the correct info from your table)?

If so show us the code you are using to effect the compare. strcmp() returns 0, (i.e. FALSE), if the strings are the same, so...

Code:

if (strcmp(Field1, Field2))
{
    OutofRange = 1;
}

Code:

cout << "sc = " << sc[i].birace1 << endl;
cout << "fam = " << fam.accept_birace1 << endl;

That will write the values out, (assuming you are in a console, and have the <iostream> header included and a using namespace std; line).

And loose the empty square brackets in the strcmp() they are not needed.

>>> what being in a console means.

Basically, are you in text mode? Is your programs interface simple white monospaced characters on a black background? This is typical of a console, the alternative is you could be in a graphical user interface, in which case basic I/O routines like cout won't work.

To use cout, put this at the top of your program, with the other includes...

Code:

#include <iostream>
using namespace std;

... note <iostream> not <iostream.h>, let's start things right!

Do your other screen interactions use something like printf()?

>>> So I am not in a console.

Okay, so forget cout and printf()! sprintf() is not the same, printf() write to the screen in a console, sprintf() write to a string.

What you could do is pop the strings up in a message box, but that will get really tedious if you have a lot of records. It might be worth trying just to see if you have anything remotely sensible in your variables. Just as an experiment, put this in your loop...

Code:

MessageBox(NULL,
           sc[i].birace1,
           "sc contains",
           MB_OK);
MessageBox(NULL,
           fam.accept_birace1,
           "fam contains",
           MB_OK);

... and see if anything recognisable happens

Can you set a break point in the loop and check the values with the debugger?

Unless we can find a way of getting some info out of your program, we're not going to be able to solve this remotely.

*** EDIT ***

After thought. The MessageBox() function will stop at the point you've inserted it until the "OK" button is pressed, the message box isn't behind your window is it?. I didn't want to get into this, but instead of NULL as the first parameter, if you have the handle of your active window, put that there, that should pop it up in front of that window.

You could also try writing the values to a file and reading it after the program completes.

On the machine that has the COM object on it. Let's try something else, have a look at this little program, it outputs lines to a file called OutFile.tmp which should be created in the same directory as your COM program, (or you can always search for it!).

Code:

#include <fstream>
using namespace std;

int main()
{
    int i;
    ofstream OutFile("OutFile.tmp");
    for (i=0; i<10; i++)
    {
        OutFile << "Hello There" i = " << i << endl;
    }
    OutFile.close();
    return 0;
}

Include the header and namespace directive as for cout, (note fstream not iostream), the line ofstream OutFile("OutFile.tmp") actually opens the output file for writing. The OutFile << line is inserting lines into the file, I have just output i, but you should put your strings in there as well, the OutFile.close() closes the file.

See if you can get something out of it that way. We really must find out where the problem is. If we cannot check the contents of the strings are correct, there is no point trying to fix the compare, because we are comparing random stuff.

(I'll try to get back later, I'm going out for a while - otherwise it'll be tomorrow now - getting late!).