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Chapter 5
Mapping between Streams
Similar to connecting nodes
, this method of data mapping does not requ ire you to set essential
fields beforehand. With this method, you simply connect from one stream to another using Map to
from the Data Mapping pop-up menu. This type of data mapping is useful for mapping to t erminal
nodes and copying and past
ing between streams. Note: Using the Map to option, you cannot map
to Merge, Append, and all types of source nodes.
Figure 5-47
Mapping a stream from its Sort node to the Type node of another stream
To Map Data between Streams
E Right-click the node that you want to use for connecting to
the new stre am.
E On the menu, click:
Data Mapping > Map to
E Use the cursor to select a destination node on the target stream.
E In the dialog box that opens, ensure that fields are properly matched and click OK.
Specifying Essential Fields
When mapping to an existing stream, essential fields will typically be specified by the stream
author. These essential fields indicate whether a particular field is used in downstream operations.
For example , the existing stream may build a model that uses a field called Churn. In th is stream,
Churn is an essential field because you could not build the model without it. Likewise, fields used
in manipulation nodes, such as a Derive node, are necessary to der ive the new field. Explicitly
setting such fields a s essenti al helps t o ensure that the pr oper fields in the new source node are
mapped to them. If m andatory fields are not mapped, you will receive an error message. If you
decide that certain manipulat ions or output nodes are unnecessary, you can delete the nodes from
the stream a nd remov e the appropriate fields f r om the Essential Fields list.