Using execution order

By default, map execution occurs in the order that the destination attributes appear in the Table tab. Only destination attributes that have transformations are executed. Often, the execution order is the order in which the destination attributes are defined in the destination business object. Figure 33 shows an execution order of the map A-to-B in which destination attributes are executed in the order they are defined.

Figure 33. Default execution order

Note:
Figure 33 assume that all destination attributes have transformation code.

However, certain attributes might have dependencies in their execution order. To ensure that the transformation code of certain attributes is executed before the transformation code of other ones, you can specify the order of their execution. You can change the execution order to specify data flow. For example, suppose in the map A-to-B that Attr7 needs to execute immediately after Attr3 (in other words, Attr7 needs to execute before Attr4). Figure 34 shows how a sequence specification in the destination business operation changes the sequence.

Figure 34. Changing execution order

You can specify an explicit execution sequence that overrides the default order from the Table tab of Map Designer Express. To specify the sequence of transformations between two destination attributes in the Table tab, click in the Exec. Order field for the destination attribute whose execution order you want to change and enter the desired execution order value.

Note:
You can specify whether Map Designer Express renumbers the execution order for any attributes affected by this change with the option Defining Map: automatically adjust execution order. By default, this option is disabled. When the option is enabled, Map Designer Express automatically adjusts the execution order of other attributes. You can change the setting of this option on the General tab of the Preferences dialog. For more information, see "Specifying General Preferences".

By default, the Table tab displays attributes in the order their transformations are defined. You can then choose to display these mapped attributes by their execution order, their attribute names, or ordered by any other column of the attribute transformation table. Just click the heading of the column to order the attributes by that column's value.

Important:
If you click the row header of the transformation and drag-and-drop the transformation to a new position, you change the order in which the transformation rule is displayed. However, this action does not affect its execution order.

Copyright IBM Corp. 2003