---
sourceDocument: Yokohama ServiceNow AI Platform Administration
sourceDocumentLink: https://www.servicenow.com/docs/r/yokohama/platform-administration

 Release :

    - yokohama

ft:locale :

    - en-US

ft:publication_title :

    - Yokohama ServiceNow AI Platform Administration

ft:clusterId :

    - platadm

bundleId :

    - platadm

workflow :

    - Platform


---

# Add and customize a field in a table

# Add and customize a field in a table {#ariaid-title1}

* Release version: Yokohama
* 
* Updated January 30, 2025
* 
* ![](https://www.servicenow.com/docs/portal-asset/ico-clock) 1 minute to read

Administrators can add new fields to a table to store and display data.

## Before you begin

Role required: admin

## About this task

Note:  
Certain ServiceNow AI Platform subscriptions include custom table entitlements. You can create custom tables for any purpose, up to the entitlement limit in the subscription. To learn more about how your usage administrator maps the custom tables that you create to subscriptions, see [Map custom tables to a product subscription in Subscription Management](https://www.servicenow.com/docs/EBhLndo7fdwgyGMGMirjlg "Maintain accurate entitlement for custom tables in the global scope and stay in compliance by mapping the tables to a product subscription in Subscription Management. Mapping your custom tables keeps your custom table allotment updated and helps you avoid running out of custom table entitlements.").  
Be aware of these database limitations:

* The system can only have a maximum of 1000 columns per table. Although 1000 columns is a specified limit, this limit doesn't mean you can physically have 1000 columns within a table. The number of columns within a table is defined by the database used in the ServiceNow datacenter, not by the ServiceNow AI Platform.
* Every table, regardless of storage engine, has a maximum row size of 65,535 bytes. Storage engines may place additional constraints on this limit, reducing the effective maximum row size.
* The system can't have more than 10 medium-length or longer String fields to a single table. Attempting to save a large number of characters in 11 or more String fields can result in the following error: Syntax Error or Access Rule Violation detected by database \[Row size too large (\> `8126`)\].
* When you create fields, the u_ prefix is automatically added to the column name. If the column label that you enter contains leading numeric characters, they are replaced by the u_ prefix.
{#t_CreatingNewFields__ul_ac3_jfw_wpb}

For more information on database limitations and general questions on tables in your ServiceNow instance, see [KB0749585](https://support.servicenow.com/kb?id=kb_article_view&sysparm_article=KB0749585).

## Procedure

1. Navigate to any form.
2. Right-click the form header and select ConfigureForm Layout.
3. In the Create new field section, fill in the following fields

   | Option | Description |
   | Name | Enter the name of the field as you want it to appear on forms and lists. |
   | Type | Select a field type. |
   | Field length | Select a field length. This field is visible only for certain field types. |
   |-|-|

   {#t_CreatingNewFields__choicetable_qj4_3rw_1r}
4. Click Add.
5. Use the slushbucket to place the field in the desired location on the form.
6. Click Save.  
   The field now appears on the form in the designated location.
{#t_CreatingNewFields__steps_eb1_3b3_rs}

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