Modifying Unions

After you configure one or more Unions according to the instructions outlined in Creating Unions, you have the option to modify, delete, or create a copy of any Union you have created. To do this, you can use the Message Analyzer commands that appear in the My Items category of the Manage Unions dialog. These commands are available from the context menu that displays in the Manage Unions dialog whenever you right-click a Union in the My Items category of the dialog. You can access the Manage Unions dialog by clicking the Unions item on the global Message Analyzer Tools menu and selecting the Manage Unions item. To edit a Union in the My Items category, you must right-click the Union you want to edit and then select the Edit command from the context menu that appears. This action displays the Edit Union dialog from where you can modify the Union. The other commands in this context menu are Create a Copy and Delete, as described in the next section.

Commands for Modifying Unions

After you right-click a Union in the My Items category, you can make use of the following commands to modify it.

• Edit — click this command to open the Edit Union dialog, in which you can use the same controls to modify a Union that you use when creating a new Union, as described in Creating Unions. The modifications that you can perform or effect from the Edit Union dialog are listed below.

  • Edit a Union name — edit a Union name by entering your changes in the Name text box.

  • Change a Union category — select a different category for the Union from the Category drop-down list, or enter a new category name in the Category combo box.

  • Add fields to a Union — click the Add button to open the Field Chooser Tool Window, from where you can add one or more fields, properties, or annotations to the Union, one at a time. Note that this action can result in a Type change.

  • Remove fields from a Union — highlight a field that you want to remove and click the Remove button to exclude it from the Union. This too can result in a Type change.

  • Change message data — if you add or remove fields, properties, or annotations in a Union that does not cause a corresponding Type change, and the Union Name also remains unchanged, this can result in an immediate update to the underlying message data in any active data viewer that uses the Union. This might include currently active viewers such as the Analysis Grid or Chart viewer. In addition, if a sort, group, or other operation is in progress when such a data change occurs, all active viewers will restart those operations. Lastly, you might observe that the Change Union dialog does not display in this case because a message data change is immediate and does not require a Restarting Message Analyzer.

• Create a Copy — click this command to open the Edit Union dialog that is automatically populated with a replica of the existing Union configuration. You can then modify the copy and Save it under a new Union name. By providing a Union template, this command enables you to quickly create a new Union based on similar data from an existing one. When working with a copy of an existing Union, the following guidelines apply:

  • Saving a Union copy that matches an existing name — if you try to Save a copy of an existing Union without changing its Name value, Message Analyzer displays a message to indicate that the Union name is already in use. Message Analyzer does not allow you to save such a Union because all Union names must be unique.

  • Saving an edited Union copy — if you modify a copied Union and Save it with a Union name that is different than any other Union name, Message Analyzer adds it to the Unions list in the Manage Unions dialog, whether or not a Type change has also occurred. The Union is also added to the Field Chooser window under the Unions node. Note that changes you make to a copied Union can include a Type change, for example, by adding or removing a field that causes a Type change.

• Delete — click this command to delete a Union.

  The deleted Union is then removed from the Unions list in the Manage Union dialog, as it is no longer an editable or shareable asset. Note that any Analysis Grid viewer column that contains the Union name continues to persist. However, after the Union is removed at the next Message Analyzer restart, it will no longer be available from Field Chooser and therefore you will be unable to add it as a new data column in the Analysis Grid viewer. Until such time, you can continue to display and use the Union as needed.

Restarting Message Analyzer

When you restart Message Analyzer, any changes that are queued up for one or more Unions will be applied. Note that any Union you delete in the My Items category of the Manage Unions dialog will be removed from the root Unions node in the Field Chooser window following a Message Analyzer restart.

Consumers of Changed Unions

If a changed Union is called by a Message Analyzer feature that uses the Union (for example, a Chart Layout formula or Filter Expression), Message Analyzer handles these situations within the context of existing functionality. For instance, if you attempt to create a Filter Expression that utilizes a Union that has had a Name change, or that you removed with the Delete command, an automatic compilation check that occurs before the filter is applied to a message set might display the Compile Query Error dialog. This dialog indicates that the Filter Expression failed to compile because the Union entity could not be found. Note that a similar process takes place for Pattern Expressions, which are also subject to a compilation check.

See Also

Creating Unions
Refreshing Data Views Containing Unions