> For the complete documentation index, see [llms.txt](https://docs.docbits.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.docbits.com/administration-and-setup/settings/global-settings/document-types/table-columns/adding-a-new-column.md).

# Adding a new Column

Add a column when a value has to be captured per line item that the default columns do not cover, a cost centre, a project number, an internal article number.

## Before you start

* Decide which **table** the column belongs to. Most document types have one table (for example `INVOICE_TABLE`). If the list is empty, click **Create new table** first; the dialog asks only for a table name.
* Decide the **type**: `AMOUNT` for money, `NUMBER` for quantities, `DATE`, `BOOLEAN` for yes/no, `CURRENCY` for an ISO currency code, `STRING` for everything else. The type cannot be changed after saving.
* Check whether a **default column** with the same meaning already exists but is hidden. Hidden columns are listed with the *Hidden* flag set, unhide it instead of creating a duplicate.

## Steps

1. Open **Settings → Global Settings → Document Types → Table Columns**.
2. Click **Add new table column**.

<figure><img src="https://578966019-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FT2n2w4uDCJvv7CJ5zrdk%2Fuploads%2Fgit-blob-330a6ee158ee283688866d13a595cfff6e6091f8%2Ftable-columns_add-dialog.png?alt=media" alt="Add new table column dialog with Title, Is column required, Select column type and Select Table"><figcaption><p>Add new table column</p></figcaption></figure>

3. Fill in the dialog:

| Field                   | What to enter                                                                                                                                                           |
| ----------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Title**               | Label the user sees on the validation screen, for example `Cost Centre`. Letters and numbers only. DocBits derives the technical *Column name* from it (`COST_CENTRE`). |
| **Is column required?** | Tick when the document must not be approved while the column is empty in any row.                                                                                       |
| **Select column type**  | See the type list above.                                                                                                                                                |
| **Select Table**        | The table that gets the column.                                                                                                                                         |

4. Click **Proceed**. The column appears in the list with *Read Only*, *Hidden* and *Use AI* unset. Switch those flags in the list if needed, see [Editing and deleting columns](/administration-and-setup/settings/global-settings/document-types/table-columns/editing-and-deleting-columns.md).

## After adding

* The column is **empty on existing documents**. It is filled on documents uploaded or restarted after the change.
* For suppliers with **trained rules**, open one of their documents in table training and map the new column, or the column stays empty for that supplier. See [Defining tables and columns](/administration-and-setup/setup/document-training/training-line-fields-table-training/defining-tables-and-columns.md).
* With **AI table extraction**, the AI fills the column if the value is recognisable on the document. Mark the column *Use AI* if the supplier has trained rules but this column should still come from the AI.
* Add the column to the **export mapping** if the ERP should receive it, see [Export](/administration-and-setup/settings/document-processing/export.md).

## Messages

| Message                                                                    | Meaning                                                                                       |
| -------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------- |
| *Column name already exists*                                               | A column with this technical name is already in the table. Choose a different title.          |
| *Column name already exists – Please activate it in Table Column settings* | A hidden default column has this name. Unset its *Hidden* flag instead of creating a new one. |
| *No table exists. Please create table before creating columns.*            | The document type has no table yet: click **Create new table** first.                         |


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