Structured Query Language

databases

Definition

Structured Query Language

Structured Query Language (SQL) is a domain-specific language used to manage data, especially in a relational database management system (RDBMS).

Sublanguages

Data Definition Language (DDL)

Data Definition Language (DDL)

Defines and modifies the structure of database objects such as tables, indexes, and schemas using commands like CREATE, ALTER, and DROP.

Data Manipulation Language (DML)

Data Manipulation Language (DML)

Manages data within schema objects, allowing for data retrieval, insertion, updating, and deletion using commands like SELECT, INSERT, UPDATE, and DELETE.

Data Query Language (DQL)

Data Query Language (DQL)

Focuses on querying data from the database, primarily using the SELECT statement to retrieve data based on specific criteria.

Data Control Language (DCL)

Data Control Language (DCL)

Controls access to data within the database by granting and revoking permissions using commands like GRANT and REVOKE.

Transaction Control Language (TCL)

Transaction Control Language (TCL)

Manages transactions in the database, ensuring data integrity and consistency with commands like COMMIT, ROLLBACK, and SAVEPOINT.

Statements

SELECT

Definition

SELECT (SQL)

A SELECT statement in SQL is used to retrieve data from one or more database tables, or expressions. It allows you to specify which columns you want to see, from which tables, and can include conditions to filter the rows returned. The result of a SELECT statement is a temporary table called a result set.

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