ODBC core SQL grammar: Which statement best reflects what the ODBC “core” level guarantees in terms of SQL statements and features?

Introduction / Context:
ODBC defines levels of SQL grammar support so that applications know what to expect across different DBMS drivers. The core (or minimum) grammar specifies a foundational subset of SQL statements that every compliant driver must implement, ensuring baseline portability.

Given Data / Assumptions:

• We are distinguishing between basic (core) and extended SQL features.
• Core support should enable CRUD operations and simple retrieval.
• Advanced SELECT features such as complex subqueries may require higher compliance levels.

Concept / Approach:
The ODBC core (minimum) grammar guarantees INSERT, UPDATE, and DELETE, as well as a basic SELECT capability. More advanced constructs (extensive subqueries, outer joins, set operations) are associated with higher levels (core/extended distinctions vary by ODBC version, but the intent remains: basic portability first, advanced features optionally).

Step-by-Step Solution:

Verification / Alternative check:
ODBC conformance documentation historically separates minimum/core grammar from extended features; many drivers advertise their supported level.

Why Other Options Are Wrong:

• Stored procedures only: Not the purpose of the core grammar.
• Full SELECT with subqueries only: Overstates core support; such features can be optional or extended.
• Only INSERT and UPDATE: Omits DELETE and basic SELECT, both essential.
• None of the above: Incorrect because option a matches the core intent.

Common Pitfalls:
Assuming all drivers fully support every advanced SQL feature; ODBC levels exist precisely to set expectations for cross-DBMS compatibility.

Final Answer:
INSERT, UPDATE, and DELETE (plus a basic SELECT without subqueries).