The Union transformer allows you to combine multiple streams into one. Providing what is equivalent to a union of tables. Use it to fuse data streams coming from different source tables. You can define new fields whose values represent whatever is available from one of the input streams.
Below is an example of a job with the Union transformation and a composite datastore . The composite datastore contains several data sources, each with customer information. The Union transformer in this example aims to combine tables of these data sources so that a single stream of data can be consumed with records from all the sources.
The configuration of the Union transformation is done by lining up column from the sources that should be combined. In the example shown 'CUSTOMERNUMBER' and 'id' are combined into one new field. Similarly 'CUSTOMERNAME' and 'family_name' is combined and so on.