令和元年度 秋期 ITパスポート試験 問64

※ Our check while writing this explanation could not fully confirm the published answer; scoring follows IPA's official key.

• ×Incorrectア

  Preventing accidental modification or deliberate falsification is the goal of ensuring data integrity, access rights, auditing, and the like; it is separate from exclusive control, which arbitrates conflicts of simultaneous access. Exclusive control is “control of concurrent execution,” not a countermeasure against falsification itself.

• ×Incorrectイ

  Making data and programs mutually independent to ease maintenance and management describes “data independence,” a benefit of the DBMS separating data structures from applications; it has nothing to do with exclusive control.

• ×Incorrectウ

  Allowing only specific people to access data according to its confidentiality level is the goal of “access control (access-rights management)” or security. It concerns controlling who is allowed to access, so its purpose differs from exclusive control, which protects consistency under simultaneous access.

• ○エ

  正解 Exclusive control (locking) is a mechanism that temporarily reserves (locks) data while one program is updating it, so that other programs cannot access or update that same data at the same time. Without it, when multiple programs read and write the same data simultaneously, problems such as a “lost update” (where one update overwrites another) can occur and break data consistency. Choice エ, “Prevent data inconsistency when multiple programs access the same data simultaneously,” is exactly the purpose of exclusive control, so it is correct.