Data is the carrier of information, it is the description attribute of objective things, and all characters can be input to the computer and can be computer recognition and processing of symbol set,

Data object refers to the collection of data elements have the same nature, is a subset of the data,

Data element is the basic unit of data, usually regarded as a whole,

Data items are the inseparable the smallest unit of data element


Data correlation between called structure, therefore, the data structure is a mutual relationship between one or more specific set of data elements,