What is the database system catalog that stores metadata about tables, views, and constraints?

• A. Attribute
• B. Data Dictionary
• C. Block
• D. Clause

Answer: (B)

The data dictionary is the database system catalog that stores metadata about tables, views, constraints, and other schema objects. This centralized store describes the structure of the database—table and column definitions, data types, constraints, indexes, views, permissions, and more—so the DBMS can validate queries, enforce rules, and plan execution. The actual user data sits in tables, while metadata about those objects lives in the data dictionary, which the system uses behind the scenes.

Other terms don’t fit because they don’t represent a centralized repository for schema metadata: an attribute is a column property, a block is a storage unit, and a clause is part of SQL syntax.