Understanding design-time and run-time connections in Dreamweaver

What are design-time and run-time connections?

There are two possible types of database connections involved when creating and testing dynamic database-driven web pages in Macromedia Dreamweaver MX: (1) the design-time connection and (2) the run-time connection. You use the design-time connection when working inside of Dreamweaver MX creating recordsets and applying server behaviors. You use the run-time connection when testing a completed dynamic page in a web browser or in the Dreamweaver MX Live Data mode.

Having separate design-time and run-time connections can oftentimes solve database connection errors within Dreamweaver MX. Separate connections can also usually speed up development time when working in Dreamweaver MX. When using separate design-time and run-time connections, the design-time connection will use a local database driver, a local DSN, and/or a local copy of the database, installed on the same machine that Dreamweaver MX is installed on. The run-time connection will use the driver and database on the testing server, which is also most likely your production server.

When should you use a separate local design-time connection?

Separate design-time and run-time connections are not required for all users. In fact, some of the Dreamweaver MX server models and platforms do not offer users a choice of using separate connections. However, many Dreamweaver MX users will have a choice and here are some reasons that you may want to consider using separate connections:

Examples of typical errors that may occur:

Which Dreamweaver users can and cannot use a separate local design-time connection?

Platforms and server model combinations where you can use separate design-time connections:

Platforms and server model combinations where you cannot use separate design-time connections:

How to use a local design-time connection

The database connection dialog box in Dreamweaver looks different depending on the server model, platform, and driver type, but in general, you want to select the radio button option that says something like "Using Driver On This Machine" or "Using Local DSN". You do not want to select the radio button option that says "Using Driver On Testing Server" or "Using DSN on Testing Server". Here are some examples:

If you are using a DSN, make sure that the name of the DSN on your local machine exactly matches the name of the DSN on the server.

If you are working on an ASP site using a connection string to an Access database there are a few different ways to proceed:

Using local design-time connections to troubleshoot database connection errors

When you specify "Using Driver On Testing Server" or "Using DSN on Testing Server" in the connections dialog box, Dreamweaver automatically uploads an MMHTTPDB script file to the testing server in order to manipulate the remote database driver via the HTTP protocol. You will notice the MMHTTPDB script files inside the _mmServerScripts folder, located in the root of your website. While HTTP remote database connectivity works fine for most users, several types of FTP or network problems can occur:

Note:Dreamweaver's Site window hides the _mmServerScripts folder. You can see the _mmServerScripts folder if you use Windows Explorer, Finder on the Macintosh, or a third-party FTP client.

When you specify "Using Driver On This Machine" or "Using Local DSN" the driver is on the same machine as Dreamweaver, so no network communication is necessary to get to the database driver. As a result, FTP and network problems are eliminated and Dreamweaver can access the database quicker and easier. The testing server does not even need to be running, unless that server also houses the database.

If I specify a local driver or DSN for my connection in Dreamweaver, will visitors to my website use the database on my local machine or on the server?

Some users may be concerned that if they specify "Using Driver On This Machine" or "Using Local DSN," which connects to a local copy of the database, website viewers will be connecting to this local copy of the database. This will not be the case. Dreamweaver itself will connect to your local database to make recordsets and server behaviors, however, your website visitors will be connecting to the database on the server.

This is because they will be viewing the web pages from the server: http://www.myserver.com/mypage.asp. Since they are requesting to see the page from "myserver.com," they will be using the DSN or driver located on "myserver.com." The only way visitors could theoretically use the local copy of the database would be if you gave them your workstation's IP address, or if they logged onto your machine in person and typed http://localhost/mypage.asp, neither of which would occur under most circumstances.

Why can't I use a local DSN or local driver in ASP on a Macintosh?

The Macintosh does not have native ODBC drivers or OLE DB providers, both of which are technologies specific to Windows. Therefore, Macintosh users cannot use a local DSN, local ODBC driver or local OLE DB provider. "Using Driver On Testing Server" or "Using DSN on Testing Server" are the only options for Macintosh users with sites using the ASP server model.

Using local versions of application servers to troubleshoot database connection errors

As mentioned above, certain server models do not offer the choice to use a local driver: ASP.NET, PHP and ColdFusion (Dreamweaver MX code model). They always use the driver on the testing server, however, you can turn your local machine into a testing server.

All of the server models supported by Dreamweaver MX have servers that can be installed locally on the same machine on which Dreamweaver is installed.

Note:Macintosh users should read Using Dreamweaver with server-side technologies on a Macintosh (TechNote 16487).

If you are having trouble connecting to a database within Dreamweaver, you may want to install local versions of the application server. This would allow you to set the testing server to point to your own machine, eliminating any possible FTP or network problems.

You could then create pages without worrying about connecting to another machine. For example, you could now go to the beach with your laptop, create your dynamic pages, and even test them in a browser using your local application server. Once finished with the pages, you could then upload them to your production server.

Additional information

For troubleshooting tips relating to database connections, please refer to: 404 Error defining database connections using FTP in UltraDev (TechNote 15711).

For more details on Macintosh configurations, please refer to Using Dreamweaver with server-side technologies on a Macintosh (TechNote 16487).

For tips on FTP, please refer to Troubleshooting FTP issues (TechNote 14834).

For information on using local web servers, please refer to Using IIS or PWS locally on Windows (TechNote 16488).

For information on using Server.MapPath in ASP, please refer to Using Server.MapPath in database connection strings (TechNote 14967).

For tips on setting up Dreamweaver to test with local and remote servers, please refer to Defining a site that uses PWS/IIS locally and FTP remotely (TechNote 15571).

For help setting up the site definition in Dreamweaver, please refer toLive Data Preview - tips and troubleshooting techniques (TechNote 14619).