# Using the Annotate Stream step

The Annotate Stream step helps you refine your data for the Streamlined Data Refinery by creating measures, link dimensions, or attributes on stream fields you specify.

If you want, you can create multiple annotations on the same field. For example, you might want to create an average measure and a sum measure on the same field. You can also annotate multiple streams to modify the same data model. Additionally, you can create and add calculated measures to the data model.

The Annotate Stream step modifies the default model produced from the [Build Model](/pdia-data-integration/extracting-data-into-pdi/work-with-the-streamlined-data-refinery/use-the-streamlined-data-refinery/building-blocks-for-the-sdr/use-the-build-model-job-entry-for-sdr.md) job entry.

![SDR workflow](/spaces/YwnJ6Fexn4LZwKRHghPK/files/NlUvHrgYc49vDNOdMW93)

After you are done annotating your data model, you are ready to [publish](/pdia-data-integration/extracting-data-into-pdi/work-with-the-streamlined-data-refinery/use-the-streamlined-data-refinery/building-blocks-for-the-sdr/using-the-publish-model-job-entry-for-sdr.md) it.

### Metadata injection support

All fields of this step support metadata injection. You can use it with [ETL metadata injection](/pdia-data-integration/pdi-transformation-steps-reference-overview/etl-metadata-injection.md) to pass metadata to your transformation at runtime.

When using metadata injection with the Annotate Stream step, you can reuse shared annotation groups that already exist, but you cannot create a new shared annotation group. If you inject a shared annotation group by providing a value for **SHARED\_ANNOTATION\_GROUP**, then the step assumes you are reusing an existing shared annotation group. As a result, any annotations defined in the ETL metadata injection step are ignored.


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