Union transformation

Overview

Union transformation is the transformation type used to combine rows from multiple compatible tables into one transformation output. Use it when several inputs share the same business structure and should be delivered as one aligned result.

Function

A Union transformation stores the transformation name, schema, historization setting, participating tables, output-column layout, optional star and predefined-transformation metadata, and persistence settings. The editor focuses on the Tables and Columns grids because the main task is aligning multiple table inputs into one output structure.

The first table acts as the reference structure for the union. Its output columns define the column names and sequence used by the other tables. When another table sequence is selected, AnalyticsCreator keeps its column list aligned with the first table and removes column entries that no longer exist in the reference structure.

Use Table SeqNr to switch the column grid between the union members. For non-reference tables, Fill columns helps match the aligned column names to the selected table by column name or friendly name.

Use the table-level Union all, Distinct, and Filter Statement fields to control how individual inputs participate in the combined result. Use Persist table and Persist package when the union output should also be materialized through a persistence package.

Access

Create a Union transformation from the Transformation Wizard by selecting Union, or open an existing one from the transformation list. Union transformations can also be opened from the architecture diagram when the transformation is shown there.

How to access

Navigation tree

Schema -> Transformations -> open a union transformation

Toolbar

ETL -> New -> New Transformation or ETL -> List -> Transformations

Diagram

Open an existing union transformation node from the architecture diagram when present

Visual element

Transformation editor -> TransType / Tables / Table SeqNr / Columns

Screen overview

IDPropertyDescription
1NameTransformation name used for the combined union output.
2SchemaSchema where the union transformation is maintained.
3TransTypeIdentifies the transformation as Union and switches the editor to sequence-based column alignment.
4Hist TypeDefines the historization behavior expected from the combined output.
5TablesLists the participating tables and their sequence numbers in the union.
6Table SeqNrSelects which table sequence is currently shown in the column grid.
7ColumnsDefines and aligns the output-column list for the selected table sequence.
8Column NameBusiness column name that must remain aligned across the union members.
9ReferenceSource column selected for the aligned output column in the current table sequence.
10Union allControls whether the table input keeps duplicate rows when it participates in the union.
11DistinctControls distinct handling for a table input in the union.
12Filter StatementOptional table-level filter applied to a participating union input.
13Fill columnsMatches aligned column names to source columns for the selected non-reference table sequence.
14Persist table / Persist packageOptional persistence settings used when the union output should be materialized.
15SaveStores the union tables, aligned column layout, table-level options, metadata, and persistence settings.
16Create in DWHCreates or refreshes the union transformation in the data warehouse after the definition is saved.

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