How the columns in a table are defined

Field	Type	Null	Key	Default	Extra
productID	int(11)	NO	Pri	NULL	auto_increment
categoryID	int(11)	NO		NULL
productCode	varchar(10)	NO	Uni	NULL
ProductName	varchar(255)	NO		NULL
listPrice	decimal(10,2)	NO		NULL

Common MySQL data types

Type	Description
CHAR	A fixed-length string of charcters in the ASCII character set.
VARCHAR	A variable-length string of characters in the ASCII character set.
INT	Integer values of various sizes.
Decimal	Decimal values that can contain an integer portion and a decimal portion.
DATE, TIME, DATETIME	A date, time, or date and time.

Description

The data type that’s assigned to a column determines the type and size of the information that can be stored in the column.
Each column definition also indicates whether or not it can contain null values. A null value indicates that the value of the column is unknown.
A column can also be defined with a default value. Then, that value is used if another value isn’t provided when a row is added to the table.
A column can also be defined as an auto-increment column. An auto-increment column is a numeric column whose value is generated automatically when a row is added to the table.
For more information on the MySQL data types, see chapter 17.