> ## Documentation Index
> Fetch the complete documentation index at: https://docs.caplena.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Creating a unique ID using Smart Columns

> Create a unique row identifier to safely update your data

Sometimes, your data doesn’t come with a built-in unique ID, and that’s totally fine! If you ever need to update or enrich your dataset later on, having a unique identifier is super helpful (and sometimes essential). 

Here’s how you can create and use it, and why it makes your life easier.

### Why This Matters

Whenever you want to **replace or update** data in Caplena, the system needs to know exactly which row you’re referring to. If there’s no unique ID, things can get messy. By creating a unique ID, you give each row a clear identity, making updates simple and safe, no accidental overwrites or mismatches.

### Step 1: Create a Row ID Using Smart Columns

<Frame>
  <img src="https://mintcdn.com/caplena-32172960/813oYgf2niWhoCcy/images/CleanShot-2025-09-15-at-15.17.30-(3).gif?s=e2a36763dd48fc5526db27496a2ed419" alt="Clean Shot 2025 09 15 At 15 17 30 (3)" width="800" height="379" data-path="images/CleanShot-2025-09-15-at-15.17.30-(3).gif" />
</Frame>

<Steps>
  <Step>
    Go to your project and open the **Smart Columns** panel. Select **Formula**.
  </Step>

  <Step>
    Click **Create New Smart Column**.
  </Step>

  <Step>
    Give it a name, like `row_id`.
  </Step>

  <Step>
    Set the **Output Type** to `Text`.
  </Step>

  <Step>
    Choose `Row ID` as the formula.
  </Step>

  <Step>
    Hit **Compute Preview** to see how it looks.
  </Step>

  <Step>
    Click **Create & Fill,** and you’re done!
  </Step>
</Steps>

### Step 2: Convert Smart Column to a Regular Column

Right now, smart columns are dynamic and can't be used when replacing data. But no stress, it’s super easy to turn it into a regular one:

<Frame>
  <img src="https://mintcdn.com/caplena-32172960/813oYgf2niWhoCcy/images/CleanShot-2025-09-15-at-15.22.47-(3).gif?s=a45da490b43f7f2f5c0038fba2294d6b" alt="Clean Shot 2025 09 15 At 15 22 47 (3)" width="800" height="390" data-path="images/CleanShot-2025-09-15-at-15.22.47-(3).gif" />
</Frame>

<Steps>
  <Step>
    Go back to the **Smart Columns** tab.
  </Step>

  <Step>
    Click the delete icon next to your `row_id` smart column, this **only deletes the smart logic**, not the values.
  </Step>

  <Step>
    Click the delete icon next to your `row_id` smart column. In the confirmation dialog, leave **Delete underlying column** unchecked and confirm — this **only deletes the smart logic**, not the values.
  </Step>

  <Step>
    Now the column becomes a static, regular part of your dataset, ready to use!

    <Note>
      Now that your row ID is ready, check out [this guide on how to replace data](/data-project-management/adding-replacing-data/add-replace-columns-in-your-dataset) for the next steps.
    </Note>
  </Step>
</Steps>