What does a database schema define?

A database schema defines the structure that organizes data within a database. It serves as a blueprint that outlines how data is organized, including the tables, fields, data types, and relationships among different data entities. This structured approach ensures that data is stored in a consistent manner, making it easier to manage, retrieve, and maintain integrity. A schema enables database administrators and developers to understand the organization of the data and enforce rules for data integrity, which is essential in any database management system.

Understanding the importance of a well-defined schema is critical because it directly affects data accessibility, relationships, and overall efficiency within the system. It's a foundational piece that informs how the data will be utilized and maintained throughout its lifecycle.