Standard interface for relational databases Which language has become the de facto standard for interfacing application programs with relational database systems?

Introduction / Context:
Interacting with relational databases requires a standardized way to define schema and manipulate data. Over decades, one language emerged as the cross-vendor lingua franca, enabling portability of skills and easing integration efforts across platforms.

Given Data / Assumptions:

• The question pertains to relational systems (tables, keys, set-based queries).
• We seek the language, not a specific product or a generic programming paradigm.
• “De facto standard” implies broad, practical adoption across vendors.

Concept / Approach:
Structured Query Language (SQL) is the de facto and de jure standard for relational databases, covering DDL (CREATE/ALTER), DML (SELECT/INSERT/UPDATE/DELETE), DCL (GRANT/REVOKE), and TCL (COMMIT/ROLLBACK). Vendors may extend SQL, but its core remains widely consistent.

Step-by-Step Solution:

Identify that “Oracle” and “dBASE” are products, not interface languages.Recognize “4GL” as a class of languages, not a specific standard for RDBMS.Select SQL as the cross-platform interface language.Confirm that SQL supports both schema and data manipulation.

Verification / Alternative check:
Every major RDBMS—PostgreSQL, MySQL, SQL Server, Oracle, DB2—supports SQL as the primary interface, validating the answer.

Why Other Options Are Wrong:
Oracle/dBASE: vendor products or formats.

4GL: broad category; many 4GLs still generate SQL under the hood.

None of the above: incorrect because SQL is correct.

Common Pitfalls:
Confusing an RDBMS product with the language used to interact with it.

Final Answer:
SQL