The Expression Builder tool in System Center Updates Publisher is available on the Define Prerequisite Rules, Define Applicability Rules, and Define Installed Rules pages of the Create Update Wizard and Modify Update Wizard. The following procedure describes how to use the Expression Builder to add, edit, and delete rules, and logically group the rules defined for each type of software update verification.

To create rules and group them using Expression Builder

  1. In the Create Update Wizard or Modify Update Wizard, go to the Define Prerequisite Rules, Define Applicability Rules, or Define Installed Rules page.

  2. Click the Add Rule icon, and in the Add Rule dialog box, configure the new rule by performing one of the following actions:

    • Select from one of the following rule categories:

      Create Basic rule: Creates a basic rule that checks for a specific file, file version, registry key, and so on. There are over 20 rule types available for basic rules. For more information, see Basic Rules.

      Create MSI rule: Creates an MSI (Windows Installer) rule that checks for a specific software update, product, component, or feature. For more information about Windows Installer rules, see MSI Rules.

      Use existing rule: Uses a previously created rule. The properties for the rule can be modified, if required.

    • Choose the Rule Type from the drop-down list. The rule types for the specified rule category are listed.

    • Configure the properties for the specified rule type. Information about each rule type is available in the Updates Publisher Rules section.

    • Specify a name for the rule in the Save your rule as text box to reuse the rule.

  3. Repeat the actions in step 2 to create additional rules.

  4. In the Expression Builder, use the appropriate icons to organize and group the set of defined rules. The icons are as follows:

    • Add Group icon: Groups, or nests, the selected rules. Select one or more rules, and then click the Add Group icon to add a sub-grouping of logical And/Or expressions. By default, all groupings are added as Or expressions, but can be changed to the And operator. Rules can be nested three layers deep in the Expression Builder.

    • Delete Group icon: Deletes the group for the selected rules. Select one or more updates that have been grouped together, and then click the Delete Group icon to remove the grouping.

    • Move Up icon: Moves the highlighted rule up in the list of rules.

    • Move Down icon: Moves the highlighted rule down in the list of rules.

    • Delete icon: Deletes the highlighted rule from the software update definition. Saved rules are still available in the Manage Rules dialog box.

  5. After the expression is built, use the XML View tab to view the expression in XML format.

See Also