Lock acquisition: what is the term for locks that are automatically placed by the DBMS (as opposed to locks explicitly requested by an application)?

Introduction / Context:
DBMSs can place locks automatically to enforce isolation, or applications can request locks explicitly. The question asks for the name of the system-placed variety.

Given Data / Assumptions:

• Two acquisition styles exist: automatic (by the DBMS) and manual (by the application).
• Lock mode (shared/exclusive) is separate from acquisition style.

Concept / Approach:
Implicit locks are automatically acquired and released by the DBMS as part of query and transaction processing. Explicit locks are requested directly by application code using lock statements or hints.

Step-by-Step Solution:

Verification / Alternative check:
DBMS documentation distinguishes implicit locking (default engine behavior) from explicit locking APIs or hints.

Why Other Options Are Wrong:

• Explicit locks: requested by applications, not automatic.
• Exclusive/shared: lock modes, not acquisition style.

Common Pitfalls:
Conflating lock mode (S/X) with how the lock is obtained (implicit/explicit). They are orthogonal concepts.

Final Answer:
implicit locks