Final answer:
Tables, relationships among rows in tables, and metadata are principal components of a database system, where tables store data, relationships link data across tables, and metadata describes the structure and constraints of the data.
Step-by-step explanation:
Tables, relationships among rows in tables, and metadata are all components of a database system. Databases are designed to store, retrieve, and manage data efficiently. Tables act as a structure to store data in rows and columns, where each row typically represents a record or entity, and each column represents an attribute or field of that record.
Relationships in a database are essential for linking data across various tables, often established through primary and foreign keys, which enables the join operation to retrieve related data from different tables. Metadata within a database is crucial as it describes the data's structure, including the definition of tables, columns, data types, and constraints, helping to enforce data integrity and allowing the database management system to understand and manipulate the data.