SQL
SQL, or Structured Query Language, is a standardized programming language used for managing and manipulating relational databases. It is essential for performing various database operations such as querying, updating, and managing data. Key features include:
- Data Retrieval: SQL is used to query databases to retrieve specific data using SELECT statements, allowing for flexible data extraction based on conditions and criteria.
- Data Manipulation: It enables the insertion (INSERT), updating (UPDATE), and deletion (DELETE) of data in database tables, facilitating dynamic data management.
- Schema Definition: SQL allows the creation and modification of database structures such as tables, indexes, and views using Data Definition Language (DDL) commands like CREATE, ALTER, and DROP.
- Data Control: It includes Data Control Language (DCL) commands like GRANT and REVOKE, which manage user permissions and access control to ensure data security.
- Transaction Control: SQL supports transaction management with commands like BEGIN, COMMIT, and ROLLBACK, ensuring data integrity and consistency during multiple operations.
- Standardization: SQL is a standardized language recognized by the American National Standards Institute (ANSI), ensuring compatibility across different relational database management systems (RDBMS) such as MySQL, PostgreSQL, Oracle, and SQL Server.
SQL's versatility and powerful capabilities make it a fundamental tool for database administrators, developers, and data analysts in managing and interacting with relational databases.