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Application crashes when connected to MySQL, what am I doing wrong? [message #45113]

Thu, 03 September 2015 17:07

Giorgio
Messages: 218
Registered: August 2015

Experienced Member

Hi there,
I have been learning ultimatepp for a couple of weeks now, so I am kinda of a noob. My application communicates with a MySQL server. Usually I create a connection to the server each time I need data. I put each query in a separate method. The code goes like this:

void MyApplication::MyQuery1()
{
	MySqlSession session;
	if(session.Connect("Userfoobar", "secret", "mydb","192.168.1.1",3306))
	{
		SQL = session;		
		SqlSchema sch(MY_SQL);
		All_Tables(sch);
		SQL.ClearError();
		try {
			//Here's my query
                        int ritorno = Select(SqlSum(N_BOB))
			.From(PEZZATURE)
			.Where( COMM == ~dlgSceltaPezzature.strLav3A );

		} catch(SqlExc &err) {
			Cerr() << "ERROR: " << err << "\n";
			ErrorOK("Problem retrieving data: " + session.GetLastError());
			SetExitCode(1);
		}
	}
	else {
		ErrorOK("Connection to the db failed: " + session.GetLastError());
		SetExitCode(1);
	}
}

Note that the connection is not closed, but this has been worked well for me.

Today I experienced some unexpected crashes of my application. After some investigation, I noticed that the problem happens when pressing a specific button. This button executes some instructions including two different calls to two procedures similar to the one above, let's call them Myquey1 and Myquery2. If I comment out one of the two procedures, the application does not crash. Is not important which one I comment out, the important is that only one of the procedures is called, if I call both the application crashes. So, to me, the problem is not the procedure itself.

I thought that the problem was the fact that I do not close the connection, so I added the following line in each procedure:

if(session.IsOpen()) { session.Close(); }

but the problem is still there.

Could someone help me on this?
Regards,
Giorgio

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