A database is an organized collection of data stored in tables. A database management system (DBMS) like Oracle or SQL Server is used to create and manage databases. Data is stored in tables which are organized into rows and columns. Structured Query Language (SQL) allows users to retrieve, insert, update, and delete data from the database using commands like SELECT, INSERT, UPDATE, and DELETE. Database concepts like tables, queries, and the client-server model allow for effective data storage and manipulation.