A database is a structured collection of data that allows for efficient storage, retrieval, and management of information. To interact with a database effectively, users and applications rely on a Database Management System (DBMS).
A Database Management System (DBMS) is a collection of software systems that sits on top of a database, acting as a bridge between the underlying data and users or applications. It manages data, the database engine, and the database schema to facilitate organization and manipulation of information.
The DBMS provides a comprehensive set of features including transaction management, data recovery, backups, concurrency control, user authentication and authorization, a metadata catalog, and other administrative capabilities. These features make it easier to ensure data integrity, consistency, and security.
Databases can broadly be classified into two categories based on their structure and functionality: relational and non-relational databases.
Relational databases organize data into structured tables, with relationships defined between those tables using keys (primary and foreign keys). This model offers powerful querying capabilities through Structured Query Language (SQL).
Popular open-source relational databases include MySQL, PostgreSQL, and MariaDB. Enterprise-grade relational databases include Oracle Database, Microsoft SQL Server, IBM Db2, and SAP HANA.
SQL (Structured Query Language) is used to communicate with and manipulate relational databases. It is divided into four main categories based on functionality:
CREATE, ALTER, and DROP.INSERT, UPDATE, DELETE, and SELECT.GRANT and REVOKE.COMMIT, ROLLBACK, and SAVEPOINT.A DBMS plays a critical role in modern data-driven applications by abstracting and managing the complexities of database interactions. Understanding the structure of databases and the roles of SQL components enables developers and administrators to design systems that are efficient, secure, and scalable.