Inherited fields in ServiceNow are fields that are part of a parent table and automatically become part of child tables through inheritance. This structure is foundational in the ServiceNow data model, ensuring that child tables maintain a consistent relationship with their parent tables.
Here's why inherited fields cannot be deleted from a child table:
System Design:
ServiceNow employs a table inheritance model where child tables derive fields and properties from parent tables. Deleting inherited fields from a child table would break the integrity of the data model, as those fields are shared across multiple tables.
Impact on Functionality:
Many inherited fields, such as sys_created_on or sys_updated_by, are integral to the functionality of the platform. Removing them could disrupt workflows, reporting, and auditing capabilities.
Alternative Approach:
If you want to hide or restrict access to inherited fields in a child table, you can use ACLs (Access Control Lists) to prevent users from viewing or modifying these fields. Another option is to use UI Policies or Client Scripts to control their visibility on forms.
Developer Note:
Attempting to delete inherited fields violates ServiceNow's core principles of maintaining a robust and unified data structure. The platform enforces these rules to ensure consistent behavior across all tables in the hierarchy.
Reference:
ServiceNow Developer Documentation on Table Inheritance​.
Best practices outlined on SN Pro Tips regarding scoped application development and table structures​.