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

# MANAGE DATASETS

> Review rows in Data Explorer, restore earlier versions, and delete datasets

After you create a dataset, review its rows before you train on it, and keep track of its versions as you change it.

## REVIEW ROWS IN DATA EXPLORER

Data Explorer lists every row of the dataset with its content and metadata. Click `Data Explorer` on the dataset page, or select it from the dataset's menu on the **Datasets** page. Click a row to read the whole conversation, and click `View metadata` to see its metadata.

![Data Explorer with a row open, showing its system, user, and assistant messages](https://mintcdn.com/oumi/D0vKyXNqx2ohrLV9/images/datasets-data-explorer.jpg?fit=max\&auto=format\&n=D0vKyXNqx2ohrLV9\&q=85\&s=9e480d31c32e3be15283b7a15d9313af)

Before you use a dataset, read a sample of rows and check that:

* **Training rows end with an assistant turn.** Training learns from the assistant's responses, so a row that ends on a user turn teaches nothing.
* **Labels match the responses.** For a classification dataset, the label in `metadata` should match the assistant's answer. If they disagree, the evaluation scores measure the labeling errors instead of the model.
* **Generated rows vary.** In synthesized data, scan the assistant turns for repeated openings or structure. A model trained on repetitive data learns one template.
* **Tool calls are present.** In an agent dataset, an assistant turn that calls a tool shows its calls, and its text can be empty.

Data Explorer is read-only. To change rows, select `Download…` from the dataset's menu to export the latest version as JSONL. Edit the file, and upload it as a new dataset.

## VERSIONS

Oumi creates a new version of a dataset when you delete failed rows, restore a version, or add generated rows to it. The **Versions** tab lists every version, marks the **Current Version**, and shows when each one was created.

![Versions tab with version 2 marked Current Version and the menu for version 1 open, showing Restore Version and Delete](https://mintcdn.com/oumi/D0vKyXNqx2ohrLV9/images/datasets-versions.jpg?fit=max\&auto=format\&n=D0vKyXNqx2ohrLV9\&q=85\&s=18a665b2da0ef36847901c5305e85dda)

* **Restore a version:** Open the menu of an earlier version and select `Restore Version`. Oumi copies that version into a new version and keeps the current one, so you can undo the restore the same way.
* **Delete a version:** Open the version's menu and select `Delete`. If you delete the current version, the previous version becomes current. You can't delete a dataset's only version.

To view an earlier version without restoring it, choose it in the **Version** selector on the **Overview** tab or in Data Explorer.

## DELETE A DATASET

To delete a dataset, open its menu and select `Delete`. Deleting removes the data and every version, and it can't be undone. Before you delete a dataset, check the **Used in** card on its **Overview** tab for the trainings and evaluations that used it.


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