CIS-DF Configuration Practice Question
When designing a custom class hierarchy in the CMDB, an architect must adhere to best practices to ensure optimal performance and maintainability. Which TWO of the following practices are recommended when creating and configuring custom CI classes? (Choose two.)
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Extend from an existing appropriate child class (such as cmdb_ci_server) if the new CI shares those attributes.
Best practices dictate extending from the most specific existing parent class and avoiding unnecessary custom tables when an existing class suffices.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Extend from an existing appropriate child class (such as cmdb_ci_server) if the new CI shares those attributes.
Why this is correct
Extending existing child classes leverages built-in attribute inheritance and relationship rules.
- ✗
Extend from the cmdb table directly for every new hardware type to ensure clean table isolation.
Why it's wrong here
Extending directly from cmdb bypasses standard hardware attributes and relationships.
- ✓
Avoid creating custom classes when an existing class with customized attributes or identifiers can adequately represent the CI type.
Why this is correct
Minimizing table sprawl by reusing classes with attributes or categorization is a core CMDB design best practice.
- ✗
Disable inheritance on all custom classes to improve database query execution speed.
Why it's wrong here
Inheritance is a core platform feature built into table extension and cannot be selectively disabled in that manner.
- ✗
Create a separate custom relationship table for each new custom CI class to maintain relationship integrity.
Why it's wrong here
All CI relationships must use the central cmdb_rel_ci table rather than creating custom relationship tables.
About these practice questions
This CIS-DF question is part of Courseiva's 320-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed August 2026 · checked against the official ServiceNow exam blueprint
This CIS-DF practice question is part of Courseiva's free ServiceNow certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CIS-DF exam.