Marcus, Scott (GEAE, RHI Consulting)
scott.marcus at ae.ge.com
Thu Mar 13 06:19:00 CST 2003
Drew, Calling it a lame debate because they are considered unstable shows your lack of understanding the debate. The Global debate is not centered around myth. It isn't even centered around them being unstable (they are no less stable than any other variable). The debate isn't even centered around using global variables in Access. It's built around them being sloppy coding practice in any programming language. Global variables have their use but, they lead to spaghetti code (I didn't say they are spaghetti code they LEAD TO). Do you agree that when a function that sets a global variable or uses a global variable in some calculation, where in the heck is that variable set and under what conditions is it set or not set? Sure, in a small application that is easy enough to track down. How many times have your Access applications grown into something much larger than planned for? It is a fact that globals make the code harder to read and understand. As a programmer, it is much more important that I easily understand how the code works so that I can modify it with minimal risk to error. Globals increase that risk significantly in large applications. I can't even count the number of times that I've gotten lost in the code of a large application (written by someone else) by tracking down multiple global variables used in a function. Calling it a lame debate is an excuse to ignore bad coding habits. I'm not saying that you have bad coding habits. I'm saying that they can become a bad habit. I don't personally know if you are at that level or not. I have never thought globals to be 'flaky', just a bad habit. Less than a few in an application doesn't constitute a bad habit. But having them plastered everywhere (instead of passing data as parameters in functions or subs) is a bad habit. BTW A global connection could be a good use of a global variable. Scott -----Original Message----- From: Drew Wutka [mailto:DWUTKA at marlow.com] Sent: Wednesday, March 12, 2003 5:07 PM To: 'accessd at databaseadvisors.com' Subject: RE: [AccessD] Using Global Connctions Actually, of all the 'big' debates I have seen on the list, the Global one is pretty lame. Most of the debates get into heated discussions over the fine tunings of an application, or the database engine, or even picky details of theory. The Global issue is really centered around a myth. The myth is that they are unstable. This is entirely untrue. A global variable holds a value for the life of your session. Now, in VB, when you have an .exe, or you run a project in debug mode, when you hit 'end', or stop your code, your entire project stops, so you expect your globals to disappear. However, in Access, stopping your code doesn't close forms, or shut anything down, it just stops the running code. The Globals are 'lost', but that is because your code has stopped running. Since the database still looks intact, Globals have gotten the impression that they are 'flaky'. Do you see what I am saying? Drew -----Original Message----- From: Marcus, Scott (GEAE, RHI Consulting) [mailto:scott.marcus at ae.ge.com] Sent: Wednesday, March 12, 2003 12:46 PM To: 'accessd at databaseadvisors.com' Subject: RE: [AccessD] Using Global Connctions Drew, I miss the debate we had last time on globals. Fortunately I'm not Borg so resistance is not futile. I wonder if JC is paying attention. Scott -----Original Message----- From: Drew Wutka [mailto:DWUTKA at marlow.com] Sent: Wednesday, March 12, 2003 1:31 PM To: 'accessd at databaseadvisors.com' Subject: RE: [AccessD] Using Global Connctions Love Globals. They are just as reliable as any other code. If someone did, it would be me! <VBG> Sometimes. Yes, all the time. I 'hit and release' my ADO Connections all the time, especially when on a LAN. In fact, the first vergence from that practice just happened last night. I am working on a web interface to a Contact Request database. The database is on our Internet Web Server, and the Web interface is on our Intranet Web Server. Creating the connection through the network (from server to server) takes about half a second to a second (didn't really time it...). I have multiple classes working on each page, each of which require db interaction. Opening and killing the connection creates unacceptable delays (3 to 4 seconds per page load...I know that's not too bad, but in comparison to almost instantaneous pulls with the method I am using now, there is a big difference). So what I did, was take a major 'class', which represents information about the person logged in (it's used in every page), and I load an instance of that class, if it hasn't been loaded. If it has been loaded, I pull the class from a Session variable, which has already been loaded. That class keeps the connection open while the class is live, so I can then pass the connection object to other classes, keeping it open the entire time. With that method, the first page on the site (whatever page is hit) takes a few moments to load, but from that point on, the site runs as fast as the user can click. I left the default timeout of 10 minutes on the session object, so as long as the user doesn't wait more then 10 minutes before doing something on the site, they won't experience the temporarily delay in the main class loading. Drew -----Original Message----- From: Mark L. Breen [mailto:subs at solution-providers.ie] Sent: Wednesday, March 12, 2003 3:35 AM To: accessd at databaseadvisors.com Subject: [AccessD] Using Global Connctions Hello All, As a follow up to Susan Harkins discussion on the command object, How do you guys use a global connection in your apps What I have been doing is initialising gccnn when I load the app. It is G lobal C onstant cnn. I then use this Global variable for every ADO section of code. Do you hate global variables? do you think that they are unreliable? do you think that someone is going to come in the middle of the night and wipe it out? Do you use a class or property pass it around instead? In a fat client, LAN, does anyone initialise it and close it each time? (I presume not) Just intested in your feedback Thanks _______________________________________________ AccessD mailing list AccessD at databaseadvisors.com http://databaseadvisors.com/mailman/listinfo/accessd Website: http://www.databaseadvisors.com _______________________________________________ AccessD mailing list AccessD at databaseadvisors.com http://databaseadvisors.com/mailman/listinfo/accessd Website: http://www.databaseadvisors.com _______________________________________________ AccessD mailing list AccessD at databaseadvisors.com http://databaseadvisors.com/mailman/listinfo/accessd Website: http://www.databaseadvisors.com _______________________________________________ AccessD mailing list AccessD at databaseadvisors.com http://databaseadvisors.com/mailman/listinfo/accessd Website: http://www.databaseadvisors.com