By the end of this chapter you will be able to:

• Combine data sets (a union) with a calculate stream
• Record the source for each record in a stream
• Use the internal variable _pipeName

In this exercise you will produce a single list of updates to customers' Cable TV packages. Customers can update their packages both through a customer care system and in shops. You will bring all these updates together into a single list.

Read in Data Sets from Files

For this exercise you need two files from the zip file you downloaded in  2 Using Excel Templates, step 5. The files contain updates from the two sources: the customer care service and the shop.

• <path>\train\inputData\ChannelPackages\CustomerCareUpdates\CustomerCareUpdates.txt
• <path>\train\inputData\ChannelPackages\ShopUpdates\ShopUpdates.txt

1. Create a new model with Name Channel Package Check.
2. Add a file collector to your model and load the data.
   1. PhixFlow displays a form for the new file collector. Set Name to Customer Care Updates.
   2. In the model, hover over the Channel Package Check file collector to display the context toolbar.
   3. Click  Upload Managed File. 
   4.  Navigate to the directory <path>\train\inputData\ChannelPackages\CustomerCareUpdates.
   5. Select the file CustomerCareUpdates.txt. and clickUpload.
   6. PhixFlow adds a new stream to the model, called CustomerCareUpdates.
   7. In the model, hover over the new CustomerCareUpdates stream and click Run Analysis.
   8. Check the data is loaded. There should be 8 lines of data, with columns for Customer Ref, Sales Date and Package.
3. Add another file collector to your model and repeat the process described in step 2. This time:
   1. Set the file collector Name to Shop Updates.
   2. Upload <path>\train\inputData\ChannelPackages\ShopUpdates\ShopUpdates.txt.
   3. PhixFlow loads 7 rows of data to this stream.

Combine Data Sets

1. Create a new stream in your model.
   1. Hover over CustomerCareUpdates and click  Add a new Stream.
   2. Set the Name to  Combined Updates.
   3. Drag all attributes from CustomerCareUpdates into Combined Updates.
2. Save your model layout.
3. Add a pipe from the other stream.
   1. Hover over ShopUpdates and click  Add a new Connector.
   2. Click Combined Updates to link the pipe to the output stream.
4. Double-click on Combined Updates to open its configuration form and set the attribute expressions.
   PhixFlow automatically adds a reference to the input pipe name at the start of each expression. To make the union work, you need to update the expression for each attribute to remove the in. prefix. Change in.CustomerRef to CustomerRef.
5. Press  in the main stream configuration form.
6. Run analysis on Combined Updates.
7. Check that you have the correct number of records in this stream when the analysis is complete.
8. Check the data set you generated to make sure that every field in every output record has been populated.

Record the Source for Each Update

You will now update your configuration to record the source for each update, in the set of combined updates. To do this:

1. Update the name of the pipe from the stream CustomerCareUpdates.
   1. Double-click on the pipe to open its configuration form.
   2. Update the Name to CC.
   3. Press  to save your changes.
2. Update the name of the pipe from ShopUpdates to shop.
3. Double-click the stream Combined Updates to open its configuration form.
4. In the Attributes section, add a new attribute and set:
   1.  Name: Source.

   2. Expression :

      if (_pipeName == "CC",
       "Customer Care"
       ,
       "Shop"
       )

5. To make Source the first attribute in the stream, drag it to the top of the attributes list.
6. Press  in the main stream configuration form.
7. Run analysis on Combined Updates.
8. Check the output data set and make sure that the source has been recorded on each record correctly.