What is a key feature of a schema in a relational database?

A schema in a relational database serves as a blueprint for how data is organized and structured within the database. It defines the tables, fields, data types, relationships, and constraints that govern how data can be stored, retrieved, and manipulated. By enforcing a specific structure, schemas ensure data integrity and consistency, which are vital for maintaining accurate and reliable information.

The enforcement of structure is critical for relational databases, as it allows for clear relationships between different entities or tables. For instance, the schema defines primary and foreign keys that can be used to link tables, which supports complex queries and joins.

Other choices do not accurately represent the primary role of a schema in relational databases. For example, while flexibility in data types is important, the primary function of a schema is to impose structure rather than flexibility. Similarly, simplifying data access without constraints would undermine the purpose of a schema, as constraints play a crucial role in enforcing data integrity. Lastly, random sampling of datasets is a technique used in data analysis and is not directly related to the definition or purpose of a schema in a relational database.