System Settings and Constraints

Just as you can launch the Settings and Constraints Editor from Application Designer and Logical Datacenter Designer, so can you launch it from System Designer. Right-click an application or endpoint and choose Settings and Constraints.

Remember that the settings and constraints in Application Designer and Logical Datacenter Designer are interrelated so that logical datacenter constraints apply to application settings, and application constraints apply to logical datacenter settings. System Designer settings and constraints operate in the same way they do in Application Designer. In fact, System Designer provides an opportunity to override the application settings prior to final deployment. Changing settings from the System Designer overrides settings defined on the underlying application definition. These overridden settings will be used in the deployment.

Figure 4-8 shows a subset of the settings that you will see if you selected the StockQuoteApp in System Designer while viewing the Settings and Constraints window. We have highlighted the LogonMethod setting, for demonstration only, to change it from the default value (ClearText) to one of the other possible values (Interactive, Batch, or Network).

Figure 4-8

That is possible only because the same setting in Application Designer was set to Overridable. To see what we mean, Figure 4-9 was created by selecting the StockQuoteApp in Application Designer while viewing the Settings and Constraints window. Notice the boxes checked in the Overridable column.

Figure 4-9

A system can contain multiple instances of a given application definition, with each instance having different settings. To test this out, you can open an existing system diagram and drag an item already shown on the diagram from the System View as a new instance. Open the Settings and Constraints Editor on the new instance, change a setting, and then open the Settings and Constraints Editor on the original instance to confirm that it isn't reflected in that instance.

Important

Additional examples of using System Designer to construct deployable systems from groups of applications can be found in Tony Loton's MSDN article "Introduction to the Visual Studio 2005 System Designer" at http://www.msdn.microsoft.com/library/default.asp?url=/library/enus/dnvs05/html/vstssysdesigner.asp.