---
schema_version: "1"
id: ef9015b5765fd59530e8451164c9155c7538cc844e8efd96453fc5e43360c741
title: Considerations When Creating an Index
collection: admin
version: current
locale: en-us
portal_url: https://docs.salesforce.com/admin/current/en-us/platform/264-0-0/custom_bo_considerations.md
canonical_url: https://help.salesforce.com/s/articleView?id=platform.custom_bo_considerations.htm&release=264.0.0&type=5
source_site: help.salesforce.com
content_type: documentation
content_hash: 231a52404ac891aaee45d7a04e1123b23ee740677c859bcbbd14a0f4ac0994da
description: Plan carefully when creating an index for your custom big object. The index is used for querying and filtering the big object data and must be designed properly.
products:
  - Salesforce Platform
  - Security
release: "264"
---
# Considerations When Creating an Index

Plan carefully when creating an index for your custom big object. The index is used for querying and filtering the big object data and must be designed properly.

Keep these considerations in mind when creating the index.

- An index must include at least one custom field and can have up to five custom fields total.
- All custom fields that are part of the index must be marked as required.
- You can’t include Long Text Area and URL fields in the index.
- The total number of characters across all text fields in an index can’t exceed 100.
    
    ![Note](https://sf-zdocs-cdn-prod.zoominsoftware.com/tdta-platform-extend_click-264-0-0-production-enus/5f7d9219-b7b1-4552-8891-f1aba9b289fc/images/icon_note.png)
    
    Note Email fields are 80 characters. Phone fields are 40 characters. Keep these lengths in mind when designing your index because they count toward the 100 character limit.
- After you’ve created the index, you can’t edit or delete it. To change the index, you must start over with a new big object.
- Design your index so that you assign the most frequently used field in a query filter to Index Position 1. The order in which you define the fields determines the order that they’re listed in the index.