Databases & Data Storage
SQL
Definition
Structured Query Language (SQL) is a domain-specific language used in programming and designed for managing data held in a relational database management system (RDBMS).
Why It Matters
SQL is the standard language for relational databases. For decades, it has been the primary way developers and data analysts interact with structured data, allowing them to create, read, update, and delete (CRUD) data.
Contextual Example
To get a list of all users from a `users` table, you would write a SQL query like: `SELECT * FROM users;`. To find a specific user, you would add a `WHERE` clause: `SELECT * FROM users WHERE email = 'test@example.com';`.
Common Misunderstandings
- SQL is a declarative language: you describe *what* data you want, and the DBMS figures out *how* to get it.
- While there is an ANSI/ISO standard for SQL, most database systems have their own minor variations or extensions (e.g., T-SQL for Microsoft SQL Server, PL/pgSQL for PostgreSQL).