> For the complete documentation index, see [llms.txt](https://docs.pentaho.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.pentaho.com/pdia-data-integration/10.2-data-integration/advanced-topics-pentaho-data-integration-overview/work-with-the-streamlined-data-refinery/use-the-streamlined-data-refinery/building-blocks-for-the-sdr/using-the-annotate-stream-step/use-the-annotate-stream-step/creating-link-dimensions/create-a-dimension-key.md).

# Create a dimension key

Before your link dimension can be used by others, you must create a dimension key for the shared dimension to link to.

**Note:** You can create multiple annotations on the same field. For example, you might want to create an attribute and a dimension key on the same field, such as Year, in your time dimension.

1. If you haven't done so already, complete steps 1-7 in [Use the Annotate Stream step](/pdia-data-integration/10.2-data-integration/advanced-topics-pentaho-data-integration-overview/work-with-the-streamlined-data-refinery/use-the-streamlined-data-refinery/building-blocks-for-the-sdr/using-the-annotate-stream-step/use-the-annotate-stream-step.md).
2. From the list in the **Annotations** table, choose a field to use as the dimension key by double-clicking it.

   For example, you may want to use the field `Calendar Year` as the dimension key for the shared dimension `Year`. Optionally, you can select the field in the **Annotations** table and then click the **Edit** (Pencil icon) in the upper-right corner.

   The Annotate dialog box appears for the selected field.
3. Select **Create Dimension Key** from the **Actions** drop-down menu for the field.

   The **Name - Value** table auto-populates with the name and value of the dimension key. You can edit the value to use as the dimension key.
4. Click **OK** to save the annotation and close the dialog box.

   In the [Shared Dimension](/pdia-data-integration/10.2-data-integration/advanced-topics-pentaho-data-integration-overview/work-with-the-streamlined-data-refinery/use-the-streamlined-data-refinery/building-blocks-for-the-sdr/using-the-shared-dimension-step-for-sdr.md) dialog box, the selected field will now appear with the summary that it is the key for the shared dimension. For example, the field `Calendar Year` may display `Calendar Year is key for dimension Year` in the **Summary** column.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.pentaho.com/pdia-data-integration/10.2-data-integration/advanced-topics-pentaho-data-integration-overview/work-with-the-streamlined-data-refinery/use-the-streamlined-data-refinery/building-blocks-for-the-sdr/using-the-annotate-stream-step/use-the-annotate-stream-step/creating-link-dimensions/create-a-dimension-key.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.