The table is the basic unit of data storage in an Oracle database. It holds all user-accessible data. Each table is made up of columns and rows. In the employees table, for example, there are columns called last_name and employee_id. Each row in the table represents a different employee, and contains a value for last_name and employee_id.
When you create a table, you specify the table type, and define its columns and constraints. Constraints are rules that help preserve data integrity.
This section contains the following topics: