Big Data Management User Guide

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Flattening a Complex Port

Use the

Flatten Complex Port

wizard to convert hierarchical data to relational data.

In the transformation, select a complex port that you want to flatten.

Right-click the selected ports, and select

Hierarchical Conversions

Flatten Complex Port

The

Flatten Complex Port

wizard appears with the list of elements in the complex port.

In the

Select Elements

column, select the check box for each element of a struct or an array data type that you want to extract.

If you select a child element of a nested complex port, the wizard automatically selects the parent element to flatten.

Optionally, click

Flatten All

to flatten all elements of struct or data type in the complex port.

The wizard selects all elements of struct or data type in the complex port to flatten.

Click

Finish

You can see the following changes in the mapping:

For each struct element that you selected to flatten, the mapping contains a new Expression transformation

Extract_<element_of_struct_type>

with the following ports:

The complex port from which you want to extract elements.

One or more output ports for the extracted elements.

The output ports contain expressions that use complex operators to extract elements.

A dynamic port with ports from the upstream transformation

For each array element that you selected to flatten, the mapping contains a new Normalizer transformation

Flatten_<element_of_array_type>

with an input group and an output group. The output group contains the flattened normalized fields for the array element.

A final Expression transformation

Final_Flatten_Result

with a dynamic port that contains the flattened ports for the complex port and other ports in the upstream transformation.

The following image shows an example of mapping changes: