93
Building Streams
Step3: Replace the template source node. Using the Data Mapping opt ion on the pop-up menu
for the template source node, click
Select Replacement Node, then select the source node for
the replacement data.
Figure 5-45
Selecting a replacement source node
Step4: Checkmapped fields. Inthe dialog box that opens, check th atth e software is mapping fields
properly from the replacement data source to the stream. Any unmapped essential fields are
displayed in red. These fields are used in stream opera tions and must be replaced with a similar
field in the new data source in order for downstream operations to function properly. Fo rm ore
information, see the topic Examining Mapped Fields on p. 95.
After using the dialog box to ensure that all essential fields are properly mapped, the old data
source is disconnected and the new data source is connected to the stream using a Filter node
called Map. This Filter node directs the actual m apping of fields in the stream. An Unmap Filter
node is also included on the stream canvas. The Unmap Filter node can be used to rev erse field
name mapping by adding it to the stream. It will undo the mapped fields, but note that you will
have to edit any downstream terminal nodes to reselect the fields and overlays.
Figure 5-46
New data source successfully mapped to the stream