Role of the data dictionary: in a DBMS, what does the data dictionary (system catalog) typically provide to the system?

Introduction / Context:
The data dictionary (also called the system catalog) is the metadata brain of a DBMS. It enables query compilation, optimization, security checks, and tooling by describing the database's structures and rules.

Given Data / Assumptions:

• DBMS must know objects (tables, views, indexes).
• DBMS must know attributes (names, types, constraints).
• DBMS must understand relationships and ownership.

Concept / Approach:
The dictionary stores metadata, not the actual user data. It includes object definitions, column types, keys, privileges, and sometimes statistics. Without it, the DBMS could not parse queries or enforce constraints consistently.

Step-by-Step Solution:

Verification / Alternative check:
Examples: INFORMATION_SCHEMA in SQL-standard systems; pg_catalog in PostgreSQL; data dictionary views in Oracle.

Why Other Options Are Wrong:
Each individual option captures only part of the dictionary's function; the complete answer is the inclusive choice.

Common Pitfalls:
Confusing metadata (dictionary) with transactional logs or with user data storage.

Final Answer:
All of the above