In relational database management systems, users access and modify data stored in tables. SQL is specifically designed for the relational model of database management.
Each row, or record, in a table describes one occurrence of a piece of data—a person, a company, a sale, or some other thing. Each column, or field, describes one characteristic of the data—a person’s name or address, a company’s name or president, quantity of items sold.
A relational database is made up of a set of tables that can be related to each other.
Figure 1-1: Multiple tables in a database
