ServiceNow
Data Model
Foundation of all ServiceNow work. Master table hierarchy and inheritance, field types and the dictionary, relationship patterns (reference, M2M, DB views), and schema design decisions. Everything in later domains builds on this.
Every CIS-DF question ultimately tests your data model understanding — even import sets, CMDB, and reporting questions assume you know how tables extend, how fields are defined, and how relationships work. Master Part 1 and the rest of the exam gets dramatically easier. Key traps: confusing GlideList (string) vs M2M (join table), and not knowing when to extend vs create a flat table.
Part 1 Study Modules
Table Types & Hierarchy
Base tables, child table extension, abstract tables, physical vs virtual tables, scoped vs global tables. How ServiceNow's object-oriented table model works.
Field Types & Dictionary
sys_dictionary deep dive — String, Reference, GlideList, Choice, Journal, Boolean, Calculated fields. What each type stores, how it renders, and exam traps.
Relationships & Database Views
Reference (1:1), M2M (junction tables), Database Views (read-only joins), and dot-walking syntax. Inner vs outer join behavior and view limitations.
Schema Design Patterns
Schema Map tool, sys_id, sys_class_name, custom field prefixes, extend vs standalone table decisions, and naming conventions that survive upgrades.