Working with the mapping table

Some steps, such as the Output step and the XML Composer step, require that you create mappings that define how to create the target nodes.

For these steps, the Mappings tab displays the mapping table. This table contains three columns: Source, Result, and Target. The Target column displays the elements in the target structure. The Source column contains the mapping for each mapped element in the target structure. The Result column displays the status of the current mapping. The table contains one row for every level in the target data structure. While every level is shown, you only map target list nodes to source list nodes and target content nodes to source content nodes. The mapping table does not allow you to map a list node to a content node or to map a content node to a list node.

Content items have a primitive value and correspond to actual values. List items repeat in the data. Elements that have maxOccurs>1, xs:list items, and links are all represented by list items.

You must map a source item to every required item in the target structure. Start at the top of the target structure and map items from the top down. Start by mapping target list nodes to source lists nodes. As soon as you map a target list node, the target content nodes of that list are available for mapping. Map the target content nodes of each mapped list node to source content nodes.

A list mapping defines how instances in the target list are created. For each item in the source list, a target item is created, and the content mapping is computed in the context of that source item. The context is defined as all of the parent items that contain the item.

For each target node, the mapping table provides a list of valid mapping candidates. The valid candidates are evaluated based on the target position in the target tree, its parent mappings, and its data type. The valid candidates are then scored and ordered based on name similarity to the target node and path.

You can map an item in four different ways. First, you select the row in the mapping table, and then perform one of the following steps:
  1. Click the down-arrow in the Source column to display a partial list of valid mapping candidates. Then, select an item from that list.
  2. Click Auto Map to automatically map the source item that received the highest mapping score. Automatic mapping is context-sensitive. If you select a list item and then click Auto Map, the list item and all of its descendant items are automatically mapped.
As you perform the mappings on the Output step, you might determine that the target contains one or more items that you do not need. To remove an item from the target structure, select the item, and then click the delete icon in the rightmost column of the table. This action is similar to removing columns from the output link.

If you decide to change a mapping, select the item and then choose a different mapping candidate.

If you decide that you want to remove one or more mappings, select an item and click Clear Mappings.