Relational databases are made up of relations, more commonly called tables. A table is a table of data. It has a name, a number of columns and rows.

• Columns: Each column in the table has a unique name and contains different data. Additionally, each column has an associated data type. Columns are sometimes called fields or attributes.
• Rows: Each row in the table represents a different record. Rows are also called records.
• Values: Each row consists of a set of individual values that correspond to columns. Each value must have the data type specified by its column.
• Keys: The identifying column in a table is called the key or primary key. Databases usually consist of multiple tables and use a key as a reference from one table to another.