Developer Workflow Guide

10.4.0
- 10.5.3
- 10.5.2
- 10.5
- 10.4.1

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Persist Mapping Outputs

You can persist mapping outputs to save the output values in the repository and use the values in subsequent runs of the same Mapping task. You can also assign persisted mapping outputs from a previous Mapping task run to workflow variables for the current Mapping task run.

When you click the

Persistence

tab in the Mapping task

Properties

view, the Developer tool displays all the mapping outputs for the mapping. To persist any mapping output, enable

Persist

for the mapping output and select the type of aggregation to perform to return a persisted value.

When the Data Integration Service persists a mapping output in the Model repository, the Data Integration Service saves the mapping output with the Mapping task name as a key. For example, if a workflow contains four mapping tasks, each running the same mapping, the Data Integration Service saves four outputs in the Model repository.

When you persist a mapping output, you can configure a different aggregate function for the persisted value than the aggregate function you defined at the mapping level. The Data Integration Service generates more than one mapping output value. For example, the OrderDate mapping output might contain the MIN OrderDate. The persisted OrderDate mapping output might contain the MAX OrderDate.

You can bind the mapping output from a Mapping task to the input parameter of the Mapping task the next time it runs. You must persist the mapping output in a Mapping task to bind it to an input mapping parameter.

A use case for binding is to persist the latest order date that the mapping processes. The next time the Mapping task runs, the input parameter to the mapping is the last date processed. The mapping can filter the parameter source rows to include the rows with an order date greater than the last order date processed.

The following image shows the

Persistence

tab on the

Properties

view of the Mapping task:

The

Persistence

tab has the following fields:

User-Defined Output: The name of a mapping output that the mapping returns.
Persist: Enables the Data Integration Service to persist the mapping output in the repository.
Aggregate Function: The type of aggregation to perform on the mapping output to persist. Select MIN, MAX, or SUM. The default is the value from the mapping output that you define in the mapping properties. You can change the aggregate function type of the persisted mapping output. You can persist a different value in the repository than the mapping output value that you pass to workflow variables.
Description: Describes the mapping output to persist in the repository.