数据库系统数据库管理系统_数据库管理系统介绍

数据库系统数据库管理系统

数据库 (Database)

A database is a collection of related data. In database any user can efficiently access the data which users want to retrieve. It can be anything from a simple collection of roll numbers, names, addresses and phone numbers of students to a complex collection of sound, images, and even video or film clippings. Though they are generally computerized, instances of non-computerized database from everyday life can be cited in abundance. A dictionary, a phone book, a collection of recipes and a TV guides are the examples of non computerized database. The examples of computerized database include customer files, employee rosters, books catalogue, equipment inventories and sales transactions.

数据库是相关数据的集合。在数据库中，任何用户都可以有效地访问用户想要检索的数据。它可以是任何种类，从简单的学生卷名，姓名，地址和电话号码到复杂的声音，图像甚至视频或电影剪辑集。尽管它们通常是计算机化的，但可以大量引用日常生活中非计算机化数据库的实例。字典，电话簿，食谱集和电视指南是非计算机数据库的示例。计算机化数据库的示例包括客户文件，员工名册，书籍目录，设备库存和销售交易。

数据库管理系统(DBMS) (Database Management System (DBMS))

It is a collection of interrelated data usually called database and a set of programs to access, update and manage those data which form part of management system. In word, it is a software package to facilitate creation and maintenance of computerized database.

它是通常称为数据库的相互关联数据的集合，以及一组访问，更新和管理构成管理系统一部分的数据的程序。简而言之，它是一个软件包，用于促进计算机数据库的创建和维护。

It is general purpose software that facilitates creation the following...

它是通用软件，可帮助创建以下内容...

Defining
定义

It specifies the data types and structures and some constraints for data to be stored.
它指定了数据类型和结构以及要存储的数据的一些约束。
Constructing
建造中

It Helps us to construct a new database and storing data in a storage medium.
它有助于我们构建新的数据库并将数据存储在存储介质中。
Manipulating
操纵

Its helps us to manipulate existing data involving new queries, updating and generating reports.
它有助于我们处理涉及新查询，更新和生成报告的现有数据。
Sharing
分享

Its allowing the multiple users and programs to access data simultaneously. It allows multiple users to work on the same time.
它允许多个用户和程序同时访问数据。它允许多个用户同时工作。

Examples: Ms Access, Dbase, FileMaker, ORACLE etc.

示例： Access，Dbase，FileMaker，ORACLE等。

数据库需求方法 (Needs of database Approach)

Before database approach, information on a computer is stored in OS files. To allow users to manipulate the information, the system has a number of applications programs that manipulate files. This is known as File processing system.
在使用数据库方法之前，计算机上的信息存储在OS文件中。为了允许用户操纵信息，系统具有许多操纵文件的应用程序。这称为文件处理系统。
File based system uses all early attempt to computerize the manual filling Systems However, rather than a centralized approach , to steer data decentralized approach where each department store and control its data.
基于文件的系统使用了所有早期尝试来对手动填充系统进行计算机化处理。但是，不是采用集中式方法，而是将数据分散式方法引导到每个部门存储和控制其数据的位置。

数据库管理系统的优势 (Advantages of Database Management System)

Reduction of redundancies
减少冗余

In this there is a centralized control of data and DBA (database administrator) which avoids unnecessary duplication of data. It also eliminates the extra processing necessary.
通过这种方式，可以对数据和DBA(数据库管理员)进行集中控制，从而避免了不必要的数据重复。它还消除了必要的额外处理。
Elimination of inconsistencies
消除不一致

The main advantage of avoiding duplication is the elimination of inconsistencies that tend to present in redundant data files. Redundancies of data in the DBMs are controlled and multiple copies of data are consistent.
避免重复的主要优点是消除了冗余数据文件中容易出现的不一致性。 DBM中的数据冗余得到控制，并且数据的多个副本是一致的。
Shared data
共享资料

A database allow the sharing of data under its control by any number of application programs or users.
数据库允许在任意数量的应用程序或用户的控制下共享数据。

Example: the application for the public relations and payroll departments can share the same data.
示例：公共关系和薪资部门的申请可以共享相同的数据。
Integrity
廉正

Data Integrity means that the data contained in the database in both accurate and consistent. DBMS provides the function of security and some types of checks which main the data integrity.
数据完整性意味着数据库中包含的数据准确且一致。 DBMS提供安全功能和某些检查类型，这些检查主要影响数据完整性。
Security
安全

Data is of vital importance to an organization and may be confidential. Such confidential data must not be accessed by unauthorized persons. The DBA who has the ultimate responsibility or the data in the DBMS can ensure that proper access procedure is allowed.
数据对组织至关重要，并且可能是机密的。未经授权的人员不得访问此类机密数据。负有最终责任的DBA或DBMS中的数据可以确保允许正确的访问过程。
Conflict resolution
解决冲突

Since the database is under control of the DBA, he/she should resolve the conflicting requirements of various users and applications.
由于数据库处于DBA的控制之下，因此他/她应解决各种用户和应用程序的冲突要求。