How to deal with foreign key in Qt

[sjyzhxw]

else
    {
        query->prepare ("insert into Courses values (?,?,?)");
        query->bindValue (0,courseIDLine->text ());
        query->bindValue (1,courseNameLine->text ());
        query->bindValue (2,courseTeacherIDLine->text ());
 
        successful=query->exec ();
 
    }
 
    if(successful)
    {
        closeInsertCourseDlg ();
    }
    else if(!errorMsg->isVisible ())
    {
       //cannot execute the statement
    }

else
    {
        query->prepare ("insert into Courses values (?,?,?)");
        query->bindValue (0,courseIDLine->text ());
        query->bindValue (1,courseNameLine->text ());
        query->bindValue (2,courseTeacherIDLine->text ());

        successful=query->exec ();

    }

    if(successful)
    {
        closeInsertCourseDlg ();
    }
    else if(!errorMsg->isVisible ())
    {
       //cannot execute the statement
    }

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but if the SQL statement doesn't satisfy the foreign key, the program will end unexpectedly, it will not just return a false

how to change the code??

[ChrisW67]

You change the code is a way that fixes whatever you have done that causes it to crash. You have not told us where it crashes or what you have done to isolate it. Run the code in your debugger and read the backtrace to find the source of the problem in your code.

Qt will return false if the insert fails: it does not crash.

If I assume for a moment that your code crashes somewhere in what you have presented then it will be at line 16 where the pointer errorMsg is invalid or null. This code will only be executed if the insert fails.