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This article introduces the relevant knowledge of "what are the characteristics of the database management system". In the operation of actual cases, many people will encounter such a dilemma. Next, let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

The characteristics of database management system: 1, data structure; 2, high sharing, low redundancy, easy to expand; 3, high data independence; 4, data is managed and controlled by database management system (DBMS).

The operating environment of this tutorial: windows7 system, DELL G3 computer.

Database Management system (Database Management System) is a large-scale software that manipulates and manages the database, which is used to establish, use and maintain the database, referred to as DBMS.

It unifies the management and control of the database to ensure the security and integrity of the database. Users access the data in the database through DBMS, and the database administrator also maintains the database through DBMS.

It can support multiple applications and users to build, modify and query databases at the same time or at different times in different ways.

Most DBMS provide data definition language DDL (Data Definition Language) and data manipulation language DML (Data Manipulation Language) for users to define the schema structure and permission constraints of the database and to implement operations such as appending and deleting data.

The main characteristics of database management system

1. Data structure

The database management system realizes the overall structure of the data, which is not only the main feature of the database, but also the essential difference between the database management system and the file system.

First, it means that the data is not only internally structured, but also uniformly manages the data and the direct connection of the data to make it structured.

Second, it means that the data in the database is not only for one application, but for all the applications of the whole organization. For example, in the information system of a school, it is necessary to consider not only the student performance management of the academic Affairs Office, but also the student registration management, student reward and punishment management, student family member management, and student payment management of the Finance Department. at the same time, we should also consider the graduate management of the graduate school, the scientific research management of the scientific research department, the personnel management and salary management of the staff of the personnel department. Therefore, the student data in the school information system should be oriented to the application of various functional management departments and departments of the school, not just an application of student performance management in the academic Affairs Office.

2. High sharing, low redundancy and easy expansion

The database management system describes and organizes the data from an overall point of view, and the data is no longer oriented to an application, but to the whole system.

Data can be shared by multiple users and Togolese applications

Data sharing can greatly reduce the redundancy of data and avoid inconsistency between data.

3. High data independence

Data independence refers to the separation of the use of data (that is, the application) from the description of the data (that is, the organizational structure and storage of the data).

In this way, the application only needs to think about how to use the data, regardless of how the data in the database is constructed and stored.

Therefore, the changes of the parties (to a certain extent) do not affect each other.

Data independence is used to describe the degree of dependence between applications and data structures, including physical independence and logical independence of data. The lower the degree of dependence, the higher the independence.

Physical independence means that the physical structure of the user's application and the data in the database are independent of each other. DBMS is responsible for how the data is organized and stored on disk, and the application is only concerned with the logical structure of the data; when the physical storage structure of the data changes, the application does not need to modify

Logical independence means that the logical structure of the user's application and the data in the database are independent of each other. DBMS is responsible for the (global) logical structure of the data, and the application only cares about the local logical structure of the data (that is, the application view). The (global) logical structure of the data has changed, and the application does not have to modify it.

4. The data is managed and controlled by the database management system (DBMS).

Data security protection: protect data from leakage and destruction caused by illegal use

Data integrity check: control the data within a valid range, or ensure that the data satisfy a certain relationship

Concurrency control: control and coordinate concurrent operations in which multiple users or applications access the same data at the same time to ensure that correct modification results or database integrity are not compromised

Database recovery: when a hardware or software failure occurs on a computer system, it is necessary to restore the database from an error state to an already correct state

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