Creating Reverse Mappings

The default forward mappings define how to populate the objects of the current model with those of the data source model. Reverse mappings are typically used in PDM-OOM mapping when, for example, data has several sources and you want to define how the data in the OOM is inserted, updated or deleted in the PDM.

To switch to reverse mapping mode, click the left arrow at the top of the area between the Source and Target panes. The left pane is renamed to Target and the right pane to Source, and the mapping tools which appear at the top of each pane are switched:

Note: Mappings are always saved in the model on the right-hand side (the model from which you launched the Mapping Editor), whether the pane is called Target or Source.

If the access type of your data source is Read/Write (see Creating a Data Source), then each mapping that you create is, by default, bi-directional (with an arrow at each end). To create a:

Read-only (ie forward-only mapping), create the mapping in forward mode and then switch to reverse mode and select and delete it. The mapping link now becomes dotted and has an arrow only on its right end.
Write-only (ie reverse-only mapping), create the mapping in reverse mode and then switch to forward mode and select and delete it. The mapping link now becomes dotted and has an arrow only on its left end.

When you create uni-directional mappings in this way, the following types of link line can be visible:

Forward Mode	Mapping Type	Reverse Mode
	Forward and reverse (read-write) mapping
	Forward only (read-only) mapping
	Reverse only (write-only) mapping

Solid lines indicate that you can edit the details of the mapping in the Mappings pane (which, in reverse mode, is renamed to Reverse Mappings). In reverse mode, you can modify the default reverse mapping by editing the Insert, Update and Delete sub-tabs.