> For the complete documentation index, see [llms.txt](https://docs.sdv.dev/rdt/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.sdv.dev/rdt/transformers-glossary/id.md).

# ID

ID columns act as reference labels. The values generally do not have any semantic or mathematical meaning on their own.  Primary and foreign keys are examples of `'id'` columns.

![For example, the primary key column user\_id is an id column that can be used to identify each row. It has a specific format: 'ID\_' followed by a 3-digit code.](https://2225246359-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FVGX92M819eIp0rMg5elc%2Fuploads%2FNuDe0qQ1Kf1Vb8eSEMoZ%2Frdt_transformers-glossary-ID_June%2002%202025.png?alt=media\&token=59363d12-8a77-4172-86e3-9723f1ee20a4)

{% hint style="warning" %}
ID columns are not automatically detected. Please verify your data and manually set any ID columns.
{% endhint %}

## Browse Id Transformers

<table data-view="cards"><thead><tr><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><a href="/rdt/transformers-glossary/id/anonymizedfaker.md"><strong>AnonymizedFaker</strong></a></td><td>Generate text belonging to specific contexts or rulesets.</td><td><a href="/rdt/transformers-glossary/id/anonymizedfaker.md">AnonymizedFaker</a></td></tr><tr><td><a href="/rdt/transformers-glossary/id/indexgenerator.md"><strong>IndexGenerator</strong></a></td><td>Generate a countable ID index with prefixes and suffixes.</td><td><a href="/rdt/transformers-glossary/id/indexgenerator.md">IndexGenerator</a></td></tr><tr><td><a href="/rdt/transformers-glossary/id/regexgenerator.md"><strong>RegexGenerator</strong></a></td><td>Generate structured text using a regular expression format.</td><td><a href="/rdt/transformers-glossary/id/regexgenerator.md">RegexGenerator</a></td></tr><tr><td><a href="/rdt/transformers-glossary/id/treat-ids-as-categorical-labels.md"><strong>Treat IDs as categorical</strong></a></td><td>Use any of the categorical transformers to treat IDs as recyclable, categorical labels.</td><td><a href="/rdt/transformers-glossary/id/treat-ids-as-categorical-labels.md">Treat IDs as categorical labels</a></td></tr></tbody></table>


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