Data Structure 1 Introduction

1. Data: A symbol describing objective things. It is an object that can be operated by a computer. It is a collection of symbols that can be recognized by a computer and input to the computer for processing.

2. Data Element: it is a basic unit that makes up data and has a certain significance. It is usually processed as a whole in a computer. It is also called a record.

3. Data items: a data element can be composed of several data items. Data items are the smallest units that cannot be separated.

4. Data Object: a set of data elements with the same nature and a subset of data.

5. Data Structure: a set of data elements with one or more specific relationships.

6. Logical Structure and physical structure:

6.1 Logical Structure: The relationship between data elements in a data object.

6.1.1 set structure: Except for the same set, the data elements in the set structure have no other relationship.

6.1.2 linear structure: data in a linear structure is a one-to-one relationship.

6.1.3 tree structure: there is a one-to-many hierarchy between data elements in the tree structure.

6.1.4 graphic structure: the data elements of a graphic structure are many-to-many relationships.

6.2 physical structure: the logical structure of exponential data is stored in the computer.

6.2.1 sequential Storage Structure: stores data elements in address-contiguous storage units. The logical and physical relationships between data are consistent.