# How to edit a table?

The **Custom Data model editor** is where you change table structure: fields, charts, display, and record card groups. Before risky schema changes, the system shows **Review changes before save**.

## When you need this

- You need to add, rename, or change a field type.
- You want to configure charts, total row, or macros.
- You need to change the table group or record card sections.

## Key terms

- **Edit Custom Data model** — mode for an existing table; **Model name** and **Table key** cannot change after creation (used in processes).
- Editor tabs: **Model metadata**, **Fields**, **Charts**, **UI settings**, **Field display**, **Process usage**.
- **Review changes before save** — sections **Safe changes**, **Structural changes**, **Destructive schema changes**; for integrations — **Caution: model is in use**.
- **Group** in metadata — category in **Custom Data models** list, not the same as record card groups on **Field display**.

## Before you start

- [x] You are in **Menu → Custom Data**.
- [x] The table already exists.
- [x] You understand that removing fields or changing types may lose data or break processes.

## Step-by-step

1. In **Custom Data models**, find the table or select it in the **Tables** sidebar.
2. Click **Edit** — **Custom Data model editor** opens.
3. On **Model metadata**, update **Description**, **Group**, or **Purpose** if needed.
4. On **Fields**:
   - Add a field — **Add field**, pick **Type** and **Label**.
   - Expand the field card for **Validation**, **Field visibility**, **Association**, etc.
   - For advanced keys — **JSON** toggle on the right.
5. On **Charts**, add or edit chart cards (**Add card**).
6. On **UI settings**, configure **Table stylization**, **Record view (side panel)**, **Macros**.
7. On **Field display**, use **Table** / **Card** toggles and **Record card groups** (**Add group**, drag fields).
8. Click **Save**:
   - If **Review changes before save** appears — read **Destructive schema changes** and confirm.
   - If the model is in use — check **Caution: model is in use** on the usage tab.

## What happens next

Structure and UI settings are updated. The records table shows new columns; existing rows keep data in fields you did not remove.

## How to verify

- The editor closes without validation errors.
- New fields appear in the records table (if **Table** is on for them on **Field display**).
- Processes and association fields in other tables still work (verify manually if there was **Integration risk**).

## Other options

- Quick add a column from the records table — **Add field** in the toolbar (short form; full settings — **Open full editor**).
- Complex changes via **JSON** — the **JSON** toggle in the editor stays in sync with the form.

## Related guides

- [Configure field type](/en/customdata/how-to/configure-field-type.md)
- [Configure field display](/en/customdata/how-to/configure-field-display.md)
- [Create a record card group](/en/customdata/how-to/create-group.md)
- [Use the process tab on a table](/en/customdata/how-to/use-scenario-tab-on-model.md)
- [Semantic field types reference](/en/customdata/reference/semantic-field-types-reference.md)