Can you explain the principle of operation of relational databases?

Relational databases (RDBs) organize data in the form of tables consisting of rows and columns. Each table represents a set of records (rows), and columns are attributes of these records. The main principle is that data is linked through keys: a primary key uniquely identifies a record in a table, and a foreign key links records across different tables.

Relational databases use SQL language for creating, reading, updating, and deleting data. Thanks to normalization, data is structured to minimize duplication and ensure integrity.

Example: a "Users" table with fields id (PK), name, email; a "Orders" table with fields id (PK), user_id (FK), order_date. The relationship between tables allows retrieving all orders of a specific user.

Thus, relational databases provide convenient storage and management of related data using tables and keys.