SQL 数据库

附件1、外文翻译资料译文





SQL 数据库



　　SQL 数据库是在现今计算机环境中最广泛使用的数据库技术的一个类型。数据被储存在一个提供高度的功能性的非常结构化格式中。相对于其他的较旧数据库技术，SQL 数据库更健壮，更安全，性能更加优越。它为 SQL读取数据提供通路。因此，在更进一步着手进行之前，我们首先要知道什么是SQL。

SQL 是什么？

　　SQL可以读作 "sequel" 或 "seekel" 是结构化语言的首字母的缩写，该语言是由IBM 公司发明的用于处理被包含在主机计算机数据库的数据的语言。SQL所描述的核心表示关系的模型正式地在 1970 年被 E. 博士 F. Codd 定义，一个IBM研究员在他的一篇大型数据库的报告中定义了数据关系性模型。系统/ R 计划在 1974 年开始发展结构化语言。在1974-75年间，系统/ R在一个 IBM 原型上被实现，当时被称为SEQUEL-XRM。之后又包含了多表和多用户的特征被修订为SEQUEL/2，且被命名为SQL。

　　SQL 用来创建, 保持和查询表示关系的数据库和使用一般的英文单词作为它大部份它的, 使它使用更方便。SQL也时常嵌入到其他编程语言中。SQL和其他标准的编程语言的最基本的区别就是SQL是声明性的语言。你可以指明你想从数据库里得到什么类型的数据，RDBMS 负责理解该如何得到它。

SQL 标准

　　SQL,最流行的表示关系的数据库语言被美国国家标准协会首先在 1986 年标准化。自从那时以后，它已经作一种国际标准被国际标准(ISO)组织和国际电子委员会所采用。虽然SQL支持ANSI和ISO两种标准，但是许多数据库产品用对标准的语言专有的延长支持SQL 。





附件2、外文原文（复印件）





　　　　　　　　　　　SQL Databases

　　　　　　　　　　　

　　SQL database is a type of database technology that is the most widely used in today's computing environment. Here the data is stored in a very structured format that provides high levels of functionality. SQL databases are generally more robust, secure and have better performance than other older database technologies. It provides for SQL access to the data. So it is important to understand the term SQL before we proceed further.

What is SQL?

　　SQL pronounced either as "sequel" or "seekel" is an acronym for Structured Query Language, a language developed by IBM Corporation for processing data contained in mainframe computer databases. The relational model from which SQL draws much of its conceptual core was formally defined in 1970 by Dr. E. F. Codd, a researcher for IBM in his paper titled A Relational Model of Data for Large Shared Data Banks. System/R project began in 1974 and developed SEQUEL or Structured English Query Language. System/R was implemented on an IBM prototype called SEQUEL-XRM during 1974-75. Later it included multi-table and multi-user features revised as SEQUEL/2 and renamed as SQL.

　　SQL is used to create, maintain & query relational databases and uses regular English words for many of its commands, which makes it easy to use. It is often embedded within other programming languages. A fundamental difference between SQL and standard programming languages is that SQL is declarative. You specify what kind of data you want from the database; the RDBMS is responsible for figuring out how to retrieve it.