The document outlines SQL commands categorized into five types: DDL (Data Definition Language), DQL (Data Query Language), DML (Data Manipulation Language), DCL (Data Control Language), and TCL (Transaction Control Language). DDL is used for database schema creation and modification, while DQL retrieves data, DML manipulates existing data, DCL manages user privileges, and TCL handles transaction control. Additionally, the document describes database design phases, including conceptual, logical, and physical design, with examples related to an outpatient management system.