1. Data
It is a symbolic representation of information. In computer science, it refers to all symbols that can be input into a computer and processed by a computer program. Images, sounds, etc. can be attributed to the category of data through coding.
2. Data Element
It is the basic unit of data, which is usually considered and processed as a whole in a computer program. Equivalent to the "row" of the database table.
For example, the sample questions of the data structure textbook also have description examples. A checkerboard pattern in the "tree" in Example 1-2 and a circle in the "picture" in Example 1-3 are all called a data element.
3. Data Item
A data element can be composed of several data items. For example, the bibliographic information of a book in Example 1-1 is a data element, and each item in the bibliographic information (such as book title, author name, etc.) is a data item. A data item is an indivisible smallest unit of data.
4. Data Object
It is a collection of data elements of the same nature. It is a subset of the data. For example, the collection of integer data objects can be represented as N={0, ±1, ±2...}, and the collection of alphabetic character data objects can be represented as C={'A','B',...'Z'}.
5. For example: student information card record
Table: Data Object
Row: data element
Each item in the row (column): data item (indivisible data content).