Output step (DataStage®)

The Output step describes how the hierarchical data structure is mapped to a relational data structure.

The Output step provides two windows: Output and Mappings.

In the Output window, you can display two views: a Links view and a Tree view.

The Links view displays the same column definition table that you see on the Columns tab of a stage. From the Links view, you can edit the column definitions and then view the result in the step Output. When you save the assembly, the edited column definitions are saved in the job properties.

The Tree view displays the relational links structure after it is transformed into a hierarchical structure. The root element is Top, and it contains the entire output data. Each output link is transformed into a child list item of the OutputLinks node. Each column is transformed into a content item and assigned a primitive type. For example, a column that is assigned the SQL Varchar type is transformed into a content item that has the String data type.

In the Mappings window, you map the hierarchical data structure to a relational data structure.

You must map a source item to every item that is in the target structure and that you want to include in the output. Start at the top of the target structure and map items from the top down. Start by mapping target list nodes to source lists nodes. As soon as you map a target list node, the target content nodes of that list are available for mapping. Map the target content nodes of each mapped list node to source content nodes.

In the Mappings window, you can delete multiple columns from the Mappings table by selecting the columns and typing Delete from your keyboard.

For more information about mapping, see Mapping data.

Not all assemblies use an Output step. For example, if the Hierarchical Data stage is used as a target stage in a job and does not have any output links, the Output step is empty. Even if the Output step is empty, it is a permanent part of an assembly; you cannot remove it.