# Describe your data

> Write table and column descriptions and set keys and time columns, in a draft that reaches agents when you publish it.

Updated: 2026-11-09

Agents use a table's description, key, and time column to write correct SQL. Changes wait in a draft until you
[publish it](https://bonnard.ai/docs/context/review-and-publish.md#publish). To make sure that a change saved, [review the draft](https://bonnard.ai/docs/context/review-and-publish.md#review-the-draft).

## Requirements

- The Editor role or higher in your workspace.
- To work from your AI client: [Bonnard connected](https://bonnard.ai/docs/ai-clients/connect-your-ai-client.md) and access to the data source.

## Write a description

A description is the text agents read and search. For a table, say what one row is and what the table does not include. For a
column, give the unit, currency, or time zone, what its values mean, and which ones to exclude. Up to 2,000 characters.
Clear your team's description, and the database's own shows again.

### In your AI client

Ask:

```prompt
In <data source>, describe <table> as "One row per checkout. Test orders are excluded."
```

### In the console

1. In the console at `app.bonnard.ai`, select **Context**, then **Tables**, then the table. With more than one data source, select one at the top right first.
2. For a column, select it under **Columns**.
3. Select the value in the **Description** row, type, then select outside the field. The version menu at the top right reads, for
   example, `Draft · 1 change`.

[Image: The page of the orders table in Context: rows for Visible to AI clients, Description, Key, Time column, Schema, Type, and Rows]

## Set a key

A key is the columns that identify one row, so the agent knows what it can count. Use up to 8 columns that are unique
together. A primary key the database declares cannot be changed.

### In your AI client

Ask:

```prompt
In <data source>, set the key of <table> to <column>.
```

For a key of more than one column, name each one. When the database declares the key, the agent is refused with
`the database declares the key of <table> (<column>), so it cannot be changed here.`

### In the console

1. On the table's page in **Context**, select the value in the **Key** row.
2. Select the columns, then close the list to save.

When the database declares the key, the **Key** row shows it and you cannot change it.

## Set a time column

The time column is the one to filter and group by. Select the one most questions mean, for example when an order was placed.

### In your AI client

Ask:

```prompt
In <data source>, use <column> as the time column of <table>.
```

The column must hold dates or times.

### In the console

1. On the table's page in **Context**, select the value in the **Time column** row.
2. Select a column under **Date and time columns**, or **None** to clear it.

## Related

- [Connect tables with joins](https://bonnard.ai/docs/context/joins.md): add the joins your database does not declare.
- [Define metrics](https://bonnard.ai/docs/context/metrics.md): give each number one calculation.
- [Publish context changes](https://bonnard.ai/docs/context/review-and-publish.md): review the draft and take it live.