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

# Auto number

> Generate unique auto-incrementing IDs for AI Table records with custom formats combining sequence numbers, dates, and text.

Auto number generates a **unique, auto-incrementing ID** for each record. Beyond plain numeric IDs, custom rules can include creation date, fixed text, and so on.

Note: incremented numbers are not necessarily consecutive — when a record is deleted, its number is **not reused** by the next new record.

## Add an auto number field

Click + in the upper-right of the title bar — pick **Auto number** under field types.

## Set auto number type

Pick between **Incrementing number** and **Custom number**.

**Incrementing number**: starts at 1 and counts up — 1, 2, 3…

**Custom number**: define your own rule and format. Rule pieces include **incrementing number** (set digit length — once it overflows the current length, it keeps incrementing), **fixed text** (literal text as part of the ID), and **creation date** (the record's creation date as part of the ID; date format is configurable).

# FAQ

* **Q: Can a table have multiple auto number fields?**

  A: Yes.
* **Q: Are there length limits on the number / characters?**

  A: Up to 9 digits for incrementing numbers; up to 18 characters for fixed text.
* **Q: How many rule pieces can a custom number have?**

  A: Up to 9.
* **Q: Does deleting a record change other numbers?**

  A: No. Existing numbers are preserved, and deleted numbers are not reused. For example, if record 12 is deleted, the next new record is still 13.
* **Q: Can I edit a single record's number?**

  A: No — it's rule-generated. To adjust, change the rule and regenerate.
* **Q: What happens when the maximum digit length is reached?**

  A: The length grows by 1 automatically. Example: a 3-digit number rolls from 999 to 1000.
* **Q: Does sorting change the numbers?**

  A: No. Numbers are fixed and unique; sorting doesn't affect them.