The principle of database system--Introduction

Data | database
First, the introduction

1. The concept understanding of data, database, database management system and database system

A, data: is a description of the objective things of a group of words, figures and symbols, is the reflection of objective things and records. Information, which is potential in data, reflects the state characteristics of various things in the objective world, and it can increase knowledge and influence the behavior of the recipient.
B, database: is a long-term storage in the computer or media, organized, shareable data collection. It has the characteristics of low redundancy, high sharing, high independence and easy expansion.
C, DBMS: This is a user and operating system between the data management software (System software), database establishment, application and maintenance must have DBMS for unified management and control.
D, DBS: Composed of DB, DBMS and development tools, application Systems, DBAs and users.


2. Understanding of the emergence and development of database technology

Database technology is the result of the need of data Management task.
Data management refers to how to classify, organize, encode, store, retrieve and maintain the data, which is the central problem.
Data management has gone through the following three phases:
A, manual Management phase B, File system phase C, according to the library system stage

3, the research direction of data technology

The main areas of research are as follows: three.
A, the development of DBMS software: to expand the function, improve performance and improve user productivity
B, DB Design: The main task is the support of the DBMS, according to the application requirements for a department and organization to design a reasonable structure, easy to use, high efficiency of the database and application system
C, DB theory: the normative theory and relational data theory focusing on the relationship

Second, data model

1. Elements of the data model

2. Conceptual model

3. Data Model

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III. Structure of database system

1, DBS mode structure

2, DBS Architecture

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Iv. Database Management System

1, the function and composition of DBMS

2. The working process of DBMS

3, the realization of the DBMS method

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V. The engineering and application of database

1, DB design objectives and characteristics

2. DB Design method

3. DB Application