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# See and change the data behind a Mammoth dashboard

> Use the dashboard Data tab to preview rows, browse columns, chart from them, add a financial year, read What we assumed and fix stale-data banners.

The **Data** tab in the dashboard editor shows every source a dashboard reads, with actions to preview rows, open the View, browse columns and change the data. Open a dashboard you can edit and click **Data** in the side panel. Anyone who can edit the dashboard can use it; this page also covers the **What we assumed** chip and the banners that say when figures aren't current.

## Preview rows and open a dashboard's sources

Open the **Data** tab. Each source card offers:

| Action | What it does |
| --- | --- |
| **Preview rows** | Shows the source's rows in the panel (for example "Showing first 50 of 1,200 rows"). |
| **Open view** | Opens the View in the data editor in a new tab. |
| **Show in library** | Opens the source in your data library in a new tab. |
| **Change data** | Rebuilds the dashboard on different data, keeping its look and pages. Shows **Use my data** while the dashboard is on sample data. See [Change a dashboard's data or copy it](https://mammoth.io/docs/learn/dashboards/change-data-and-export/) and [Use a dashboard template](https://mammoth.io/docs/learn/dashboards/templates/#replace-a-templates-sample-data-with-your-own-data). |
| **Browse columns** | Opens the column browser (below). |

Notes you may see on a source card:

- Sample data: "Sample numbers, not yours. Use your own data to publish and share."
- A source that's been removed: "This source isn't in your library, so it can't be opened from here. The report still shows the figures it last read."
- "We can't tell where this source lives, so it can't be shown in the library."

## Add a page that reads another table

On a saved dashboard in the Dashboard format, **New page from another table** sits below the source cards. It adds a page whose charts all read a different table from the same project, up to 5 tables per dashboard. Some actions, such as **Save as template**, aren't available on a dashboard that reads more than one table. See [Pages and navigation](https://mammoth.io/docs/learn/dashboards/pages/) for the steps and limits.

## Browse a source's columns and build a chart from them

1. Click **Browse columns** on a source card. The card shows how many of the source's columns the dashboard uses, for example "6 of 14 on this board". You can also reach the same list from **Add** → **Chart** → **From your data**.
2. Read the list. **Columns in** and the source's name (for example "Columns in Sales") lists every column, grouped as **Measures**, **Dimensions** and **Dates**, with its values, range and how many rows are filled.
3. Tick up to 4 columns.
4. Click **Chart from these columns**.

Mammoth shows the charts those columns support, each with a reason, such as "12 months to follow", "Shares of one total" or "One clear leader at 41%". Two or three columns is usually enough.

How the list marks columns:

- **in use** marks columns already used by a chart, filter or KPI on the dashboard. A line above the list counts the ones that aren't.
- Columns with nothing to chart are muted with the reason, for example "One value throughout — nothing to compare" or "An identifier — one row each, nothing to compare".
- Protected attributes aren't ranked for you. Pick how you want them drawn.

If the columns can't load, you see "Couldn't read this source's columns." with **Try again**.

## Add a financial year column for your dashboard

If your data has a date column but no financial or fiscal year column, the source card shows **Need a financial year?** ("Your data has a date but no financial year column.").

1. Open **Browse columns** for that source. The prompt appears after you've done this.
2. Click **Add it in Data**. The data editor opens in a new tab, at the step that adds one.

See [Work with dates and financial years](https://mammoth.io/docs/learn/clean-and-shape/dates/).

## Check what the dashboard assumed about your data

When your data doesn't say something the dashboard needs, Mammoth makes a call and tells you. A chip above the canvas reads **1 assumption**, or for example **3 assumptions**. Click it to open **What we assumed**.

| Entry | What it means |
| --- | --- |
| "Amounts print without a currency symbol" | Nothing in your data named a currency, so figures print as plain numbers. Click **Tell the assistant** to fill the chat with "Show amounts in " and finish the sentence. |
| "Some amounts show no currency" | Some money columns have no currency. Set the dashboard's reporting currency and every figure moves together. |
| "2 totals count a repeated value" | A column joined from somewhere coarser repeats down the rows, so a total counts it more than once. |
| "2 averages weight every row alike" | Each row counts once in an average. Ask the assistant if you meant it weighted. |
| "2 tiles couldn't be built" or "2 tiles lost their columns" | Tiles that need attention. |

Ask the assistant to change any of these. Once you dismiss an entry, it doesn't come back unless what it describes changes.

## Troubleshooting stale data and failed refresh banners

A strip at the top of the canvas tells you when figures aren't current.

| Banner | Cause | Fix |
| --- | --- | --- |
| **These numbers are waiting on a refresh** | Some figures still describe the previous version. Cards still waiting show "…". | Click **Refresh**. |
| **Couldn't refresh the data** | The last data refresh failed. | Click **Try again**, or edit the dashboard to rebuild it. |
| **Some figures couldn't load their data** | Those cards show a dash. Everything else is up to date. | Click **Try again**, or dismiss the notice. The cards stay blank until their data loads. |

While an update runs, you may also see "Showing the last successful version while an update runs." For more fixes, see [Fix dashboard problems](https://mammoth.io/docs/learn/dashboards/troubleshooting/).

## Limits

- Columns ticked for **Chart from these columns**: up to 4.
- Tables per dashboard with **New page from another table**: up to 5.

## Related

- [Edit with AI in the dashboard editor](https://mammoth.io/docs/learn/dashboards/editor/): the rest of the editor.
- [Add and change charts](https://mammoth.io/docs/learn/dashboards/charts/): the **From your data** tab in the chart picker.
- [Pages and navigation](https://mammoth.io/docs/learn/dashboards/pages/): pages that read other tables.
- [Change a dashboard's data or copy it](https://mammoth.io/docs/learn/dashboards/change-data-and-export/): rebuild a dashboard on other data, or copy it.
- [Manage your dashboards](https://mammoth.io/docs/learn/dashboards/manage/): keep a dashboard's data in sync.
- [Fix dashboard problems](https://mammoth.io/docs/learn/dashboards/troubleshooting/): when a dashboard won't load or refresh.

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Source: https://mammoth.io/docs/learn/dashboards/dashboard-data.md · Updated: 2026-11-08