A data type is a type together with a collection of operations to manipulate the type. The data type defines the operations that can be done on the data, the meaning of the data, and the way values of that type can be stored. When data are assigned a type, they cannot be treated like another type under normal circumstances. For example, character data cannot be added and subtracted.
Primitive data types are predefined types of data, which are supported by the programming language. Primitive data types can hold text messages, numbers and so on, but they don't readily accommodate higher levels of complexity. For example, a programmer may create a variable called "name" and define it as a string data type. The variable will then store data as a string of characters.