Category: 04. Facts

SQL enables the definition of various constraints on database tables to enforce data integrity, such as primary keys, foreign keys, unique constraints, and check constraints. These constraints help maintain the quality and consistency of data in databases.

SQL supports transactions, which are units of work performed against a database management system. Transactions ensure data integrity by allowing operations to be either completed in full or not at all.

SQL provides several aggregate functions such as SUM, AVG, COUNT, MIN, and MAX, which allow for performing calculations on sets of values to produce summary results.

SQL allows for joining data from multiple tables using different types of joins, such as INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL JOIN. Joins are essential for combining related data from different tables.

SQL is used for various purposes such as querying databases to retrieve data, inserting new records, updating existing records, deleting records, and creating and modifying database schemas.

While SQL is a language standard, there are several popular database management systems that use SQL, including MySQL, PostgreSQL, Oracle Database, Microsoft SQL Server, SQLite, and many more.

SQL can be categorized into three sub-languages: Data Definition Language (DDL), Data Manipulation Language (DML), and Data Control Language (DCL). Each serves a different purpose in managing databases.

SQL has been standardized by both ANSI (American National Standards Institute) and ISO (International Organization for Standardization). However, different database management systems may implement the standards differently.

While many people say “S-Q-L”, the correct pronunciation is “sequel”, which stands for Structured English Query Language. It was originally developed by IBM in the 1970s.

SQL is a domain-specific language used in programming and designed for managing and manipulating data held in a relational database management system (RDBMS).