Appendix. Oracle Database SQL Primer

The Structured Query Language (SQL) is the mechanism for accessing information in relational databases. The SQL acronym has different pronunciations, but many people use the word sequel because IBM originally named it the Structured English Query Language. The SEQUEL acronym mutated to SQL when IBM discovered the original acronym was trademarked by Hawker Siddeley.

SQL is a nonprocedural programming language designed to work with data sets in relational database management systems. SQL lets you define, modify, and remove database objects, transact against data, control the flow of transactions, and query data. The SQL language commands are often grouped by function into four groups that are also called languages: Data Definition Language (DDL), Data Manipulation Language (DML), Data Control Language (DCL), and Data Query Language (DQL).