This tutorial covers the core concepts of relational databases—tables, rows, columns, and data types—along with basic operations (creating, querying, inserting, updating) and advanced topics (views, foreign keys, transactions).
is a relational database management system (RDBMS)—a system for managing data stored in relations. A relation is the mathematical term for a table: a named collection of rows. Storing data in tables is the most widely used model today, though alternatives exist. Files and directories on Unix-like systems form a hierarchical database; some systems use an object-oriented database model.
Every row in a table has the same set of named columns, and each column has a fixed data type. Columns within a row follow a defined order, but SQL makes no guarantee about the order of rows themselves—use an ORDER BY clause when a specific sort order matters.
Tables are grouped into databases. All the databases managed by a single server make up a database cluster.