Using switch() to apply multiple tests

Create a new model: Attribute Scripting
Drag the datasource CRM onto this model
From the datasource open the schema browser, find the table SOURCE_BANK_ACCOUNT_TRANS and create a database collector from it
Create a stream from this database collector – remember to use the button in the hover menu so that the stream attributes are automatically configured
Open the help for the switch() function:
- Open the section - Attribute Functions in the repository – a list of all attribute functions available in PhixFlow will appear
- Double click on the entry for switch to bring up the help page
Add an attribute to this stream to hold a description of the transaction type:
- Name: TransactionTypeDesc
- Expression: work out the transaction type description from TRANSACTION_TYPE, using a switch() statement, according to the rules below – use the examples in the help for switch() to get started
  TRANSACTION_TYPE
  Description
  1
  "Direct Debit"
  2
  "Standing Order"
  3
  "ePayment"
  4
  "Cheque"
  Any other value
  "Unknown"
Run the stream and check that your translation of transaction type to transaction type description is correct

Using forEach() to handle lists

Create an aggregate stream, with name Bank Account Summary
Add a pipe from the stream you created in the previous exercise (this is probably called SOURCE_BANK_ACCOUNT_TRANS) to Bank Account Summary
Add to the pipe the grouping:
- ACCOUNT_NUM
Drag the attribute ACCOUNT_NUM into Bank Account Summary from either the pipe or the input stream
Add an attribute:
- Name: TotalPosTrans
- Type: Float
- Expression: using a forEach loop, add up the total of all positive transactions, and store it in this attribute
Run Bank Account Summary to test this new attribute
When this is working, update TotalPosTrans to also calculate the total of negative transactions, and the total of all transactions – and hold them in local variables ($variables)
Add two further attributes – TotalNegTrans and TotalTrans - use these to store the values of all negative transactions and all transactions that you calculated in TotalPosTrans
Run Bank Account Summary again to test the new attributes

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