IPA IP 2025 Question 65
A question IPA Japan published in 令和7年度 ITパスポート試験 公開問題 問65, translated into English. ITPEC is based on the same exams.
In a DBMS, which of the following is the information that is set and used as necessary for the purpose of performing data searches at high speed?
Explanation
Index — an index is an extra lookup structure on chosen columns that lets the DBMS find rows without reading the whole table.
Like the index at the back of a book, a database index holds the values of a column in sorted or hashed form, each pointing to the rows that contain it. A search on that column then jumps to the matching rows instead of scanning every row. Indexes are optional: they are created as necessary on columns that are searched often, because each one takes storage and slows inserts and updates, which must also update the index.
Answer (a)
Why not others:
- •(b) — a foreign key refers to the primary key of another table to keep the tables' data consistent (referential integrity), not to speed up searches
- •(c) — a primary key identifies each row uniquely; it is a required part of the table's design, not information added as necessary for speed
- •(d) — a schema describes the structure of the database (tables, columns, types, relationships)
Key rule: Index = optional structure for fast searching; primary key = unique row identifier; foreign key = reference that keeps tables consistent; schema = the database's structure.
Databases · AI-written, may contain errors
This question comes from the past questions IPA Japan publishes, translated into English by ITPEC Practice. ITPEC Practice is an independent study tool and is not affiliated with IPA or ITPEC. See the original paper (PDF) or Report an issue.