ITPEC FE Morning October 2022 Question 28

Database Index — purpose of setting an index on table columns.

An index enables efficient access to data storage locations, improving search speed — like a book's table of contents.

• •Without index → full table scan (slow)
• •With index → direct lookup via index structure (e.g., B-tree)

Why not others:
- (b) — describes a UNIQUE constraint, not an index
- (c) — describes referential integrity (foreign key constraint)
- (d) — describes partitioning/sharding, unrelated to indexing

Key rule: Index = faster reads, but adds overhead on writes (INSERT/UPDATE/DELETE must also update the index).

AI-generated — may contain errors