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

 Release :

    - brazil

ft:locale :

    - en-US

ft:publication_title :

    - Brazil ServiceNow AI Platform Administration

ft:clusterId :

    - platadm

bundleId :

    - platadm

workflow :

    - Platform


---

# Rule precedence

# Precedence between data lookup, assignment, and business rules {#ariaid-title1}

Release version: Brazil  
Updated September 10, 2026  
![](https://www.servicenow.com/docs/portal-asset/ico-clock) 2 minutes to read
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## Summary of Precedence between data lookup, assignment, and business rules

This document explains the order in which various scripts, rules, and engines execute during database operations such as insert, update, or delete in ServiceNow.
Understanding this execution order is critical for customers to predict and control how business logic, assignments, and data lookups interact and affect records during these operations.
Show full answer Show less  

## Execution Order Details

Execution is divided into phases relative to the database operation:

* **Before Business Rules:** Scripts that run before the database action, with orders less than 1000 execute first, followed by those with orders greater than or equal to 1000 after engines.
* **Engines (executed without a specific order):**
  * Approval engine (for task and sysapprovalapprover tables)
  * Assignment rules engine (for task tables)
  * Escalation engine
  * Data policy engine
  * Field normalization engine
  * Role engine (synchronizes role changes for user-related tables)
  * Execution plan engine (for task tables)
  * Update version engine (for sysupdatexml table)
  * Data lookup engine
  * Workflow engine (for default workflows)
* **Database operation:** The actual insert, update, or delete occurs here.
* **After Business Rules:** Scripts that run after the database operation, with orders less than 1000 execute first, followed by those with orders greater than or equal to 1000.
* **After Engines (executed without a specific order):**
  * Label engine
  * Listener engine
  * Table notifications engine
  * Role engine (synchronizes role changes)
  * Text indexing engine
  * Update sync engine
  * Workflow engine (for deferred workflows)
  * Trigger engine (for Workflow Studio flows)
  * Email notifications (executed based on notification record weight)
  * Event-based notifications
* **Async Business Rules:** Execute asynchronously in the background after the user submits the form and after the scheduler runs the scheduled job created from the business rule. They run after the database operation but do so concurrently with other processes.

## Important Notes for Customers

* Client-side code (JavaScript running in the browser) always executes before form submission to the server, so it precedes all server-side processing.
* Assignment rules and data lookup engines execute before the actual database operation, allowing them to set or modify field values before the record is saved.
* After business rules and engines handle post-save logic, notifications, and deferred workflows.
* Async business rules provide a mechanism for background processing post-save, improving user experience by not blocking form submission.

## Practical Application

By understanding this execution sequence, ServiceNow customers can design their workflows, business rules, assignments, and data lookups to occur at the appropriate time for accurate and efficient record processing. For example, using before-business rules or data lookup engines for field population, and after-business rules or async business rules for notifications or background tasks.  
Scripts, assignment rules, business rules, workflows, escalations, and engines all take effect in relation to a database operation, such as insert or update. In many cases, the order of these events is important.
Note:  
Client-based code that executes in the browser, using Ajax or running as JavaScript, will always execute before the form submission to the server.  
The order of execution is as follows:

1. Before business rules: Scripts configured to execute before the database operation with an order less than 1000.
2. Before engines. The following are not executed in any specific order:
   * Approval engine (for task and sys_approval_approver tables)
   * Assignment rules engine (for task tables)
   * Escalation engine
   * Data policy engine
   * Field normalization engine
   * Role engine - keeps role changes in sync with sys_user_has_role table (for sys_user, sys_user_group, sys_user_grmember, and sys_user_role tables)
   * Execution plan engine (for task tables)
   * Update version engine - creates version entry when sys_update_xml entry is written (for sys_update_xml table)
   * Data lookup engine inserts or updates
   * Workflow engine (for default workflows)
   {#c_PrecBetweenAssignmentAndBusRules__ul_qgd_vdj_dq}
3. Before business rules: Scripts configured to execute before the database operation with an order greater than or equal to 1000.
4. The data base operation (insert, update, delete).
5. After business rules: Scripts configured to execute after the database operation with an order less than 1000.
6. After engines. The following are not executed in any specific order:
   * Label engine
   * Listener engine
   * Table notifications engine
   * Role engine - keeps role changes in sync with sys_user_has_role table (for sys_user, sys_user_group, sys_user_grmember and sys_user_role tables)
   * Text indexing engine
   * Update sync engine
   * Workflow engine (for deferred workflows)
   * Trigger engine (for all Workflow Studio flows)
   {#c_PrecBetweenAssignmentAndBusRules__ul_ck4_h2j_dq}
7. Email notifications. The following are executed based on the weight of the notification record:
   * Notifications sent on an insert, update, or delete
   * Event-based notifications
   {#c_PrecBetweenAssignmentAndBusRules__ul_rgj_n2j_dq}
8. After business rules (Only active records). Scripts configured to execute after the database operation with an order greater than or equal to 1000.
{#c_PrecBetweenAssignmentAndBusRules__ol_qjj_rdj_dq}  
Note:  
Like After business rules, Async business rules execute their logic after a database operation occurs. Unlike After business rules, Async business rules execute asynchronously, running in the background simultaneously with other processes. Async business rules run after the user submits the form and after the scheduler runs the scheduled job created from the business rule. The system creates a scheduled job from the business rule after the user submits the form but before any action is taken on the record in the database.
**Related concepts**   

* [Assignment rules module](https://www.servicenow.com/docs/ctjCc3QXGGV1f06tphfykg "The Assignment rules module allows you to automatically set a value in the assigned_to and assignment_group fields when a set of conditions occurs.")
* [Data lookup rules](https://www.servicenow.com/docs/ImQKbx_X_0oFdRD7E1G1mg "Data lookup rules offer a generic way to change any field value, not just assignment fields.")
* [Workflow assignments](https://www.servicenow.com/docs/0tgvH2rxefz5FFGncxEOwg "An alternative to creating data lookup or assignment rules is to create one or more workflow tasks that assign a task record as part of a workflow.")  
**Related tasks**   

* [Create an assignment rule](https://www.servicenow.com/docs/4KfuYYmdSpaumk2T2tKlZQ "Automatically assign a record according to one or more conditions in an assignment rule. Assignment rules are designed to run at the time you open a record.")
* [Create an assignment data lookup rule](https://www.servicenow.com/docs/mf5Nz~Mjt2OYrELTd~P1IA "Automatically assign a record using Data Lookup and Record Matching.")  
**Related reference**   

* [Baseline assignment rules example](https://www.servicenow.com/docs/cr7uOKkF73owaDkra9Sm0A "A baseline instance contains certain assignment rules.")  
**Related topics**   

* [Business rules](https://www.servicenow.com/docs/access?context=c_BusinessRules&version=brazil&pubname=brazil-api-reference&ft:locale=en-US)