In database systems, what does a Data Manipulation Language (DML) primarily specify to the DBMS?

Introduction / Context:
SQL is divided conceptually into a data definition language (DDL) for structure and a data manipulation language (DML) for operating on data. Understanding the DML's abstraction boundary is vital for writing portable and efficient queries.

Given Data / Assumptions:

• We refer to relational DBMS concepts.
• DML examples include SELECT, INSERT, UPDATE, DELETE.
• Optimizers choose access paths automatically.

Concept / Approach:
DML is declarative: it specifies what result is desired, not how to obtain it. The optimizer picks indexes, join orders, and execution strategies based on statistics and constraints.

Step-by-Step Solution:

Verification / Alternative check:
DBMS documentation separates DML from DDL and DCL (security) and TCL (transactions).

Why Other Options Are Wrong:
Physical layout and schema are DDL concerns; security is DCL; DML is not limited to privileges.

Common Pitfalls:
Embedding algorithmic steps in SQL; let the optimizer handle access paths and focus on correct predicates and projections.

Final Answer:
What data to retrieve, insert, update, or delete, without prescribing the low-level access path