Service Catalog and Knowledge Management
The Service Catalog lets users request items. Candidates must understand catalog items (sc_cat_item), categories, variables (questions), variable sets (reusable groups of variables), and catalog tasks (sc_task) generated on submission. Record producers create records in other tables (e.g., incidents) from the catalog. Order guides bundle items. Catalog UI policies and client scripts control variable behavior.
Knowledge Management uses knowledge bases (kb_knowledge_base), articles (kb_knowledge), and workflows for review and publishing. Know article states (draft, review, published, retired), feedback, and versioning. Knowledge blocks reuse content across articles. User criteria control who can see which knowledge base.
Traps: confusing catalog items with record producers (items create requests/tasks; producers create records in a target table). Assuming variables are fields on the item table (they are stored in sc_item_option/question_answer). And assuming knowledge articles are visible to everyone - user criteria and can read settings gate access.
Worked example: To let users report an incident through the catalog, create a record producer targeting the incident table, map variables to incident fields (short description, category), and publish it to a category. To reuse a set of common questions across items, create a variable set and attach it to each item.