DBMS与数据库
一个用于轻松组织,存储和检索大量数据的系统称为数据库。换句话说,数据库为一个或多个用户包含一堆有组织的数据(通常为数字形式)。数据库(通常是缩写的数据库)根据其内容进行分类,例如文档文本,书目和统计。但是,DBMS(数据库管理系统)实际上是用于管理数字数据库的整个系统,该系统允许存储数据库内容,创建/维护数据,搜索和其他功能。在当今的世界中,如果与访问数据的数据相关联,那么数据库本身将毫无用处。但是,越来越多的数据库用作数据库管理系统的速记。
数据库
数据库可能在其体系结构中包含不同级别的抽象。通常,这三个级别:外部,概念和内部构成数据库体系结构。外部级别定义用户如何查看数据。一个数据库可以具有多个视图。内部级别定义了数据的物理存储方式。概念级别是内部和外部级别之间的通信介质。它提供了数据库的独特视图,无论其存储方式如何。有几种类型的数据库,例如分析数据库,数据仓库和分布式数据库。数据库(更正确的是,关系数据库)由表组成,它们包含行和列,就像Excel中的电子表格一样。每个列对应于一个属性,而每一行表示一个记录。 For example, in a database, which stores employee information of a company, the columns could contain employee name, employee Id and salary, while a single row represents a single employee.
D BMS
DBMS,有时称为数据库管理器,a collection of computer programs that is dedicated for the management (i.e. organization, storage and retrieval) of all databases that are installed in a system (i.e. hard drive or network). There are different types of Database Management Systems existing in the world, and some of them are designed for the proper management of databases configured for specific purposes. Most popular commercial Database Management Systems are Oracle, DB2 and Microsoft Access. All these products provide means of allocation of different levels of privileges for different users, making it possible for a DBMS to be controlled centrally by a single administrator or to be allocated to several different people. There are four important elements in any Database Management System. They are the modeling language, data structures, query language and mechanism for transactions. The modeling language defines the language of each database hosted in the DBMS. Currently several popular approaches like hierarchal, network, relational and object are in practice. Data structures help organize the data such as individual records, files, fields and their definitions and objects such as visual media. Data query language maintains the security of the database by monitoring login data, access rights to different users, and protocols to add data to the system. SQL is a popular query language which is used in Relational Database Management Systems. Finally, the mechanism that allows for transactions help concurrency and multiplicity. That mechanism will make sure same record will not be modified by multiple users at the same time, thus keeping the data integrity in tact. Additionally, DBMSs provide backup and other facilities as well.
DBM和数据库之间的差异
A database is a collection of organized data and the system that manages a collection of databases is called a Database Management System. The database holds the records, fields and cells of data. The DBMS is the tool used to manipulate the data inside the database. However, the term database is increasingly used as shorthand for Database Management System. To make the distinction simple, consider and operating system and the individual files stored in the system. Just like you need an operating system to access and modify files in the system, you need a DBMS to manipulate databases stored in the database system.
Divinesays
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