Visual Database Tools
Columns
In a table, data is arranged into columns. Each column stores one data element, such as a first name, one line of an address, a price, or any similar discrete unit of information.
When columns are created in a table, they are given a name that identifies their purpose, such as FirstName or Address1. In most databases, you must also specify additional properties, such as how long the longest entry in the column will be, and what type of data the column will contain - characters, integers, floating-point numbers, dates or times, and so on. Other column properties can include whether the column is the table's primary key, whether users must enter a value into it, and what its default value is.