【2017年整理】计算机专业英语(数据库1).pptVIP

计算机专业英语; Unit Three Database; Unit Three Database; Unit Three Database; Unit Three Database; Unit Three Database;Word-building ： 连字符构词法 两个词语通过连字符“-”连接在一起， 构成一个包含该两个词语含义的 合成词。 例如：object-enhanced post-relational pre-relational等等 ;Sentences ： Clearly separating the three levels was a major feature of the relational database model that dominates 21st century databases. ;Sentences ： It provides a common view of the database that is uncomplicated by details of how the data is stored or managed, and that can unify the various external views into a coherent whole.;Sentences ： A database management system (DBMS) consists of software that operates databases, providing storage, access, security, backup and other facilities. ;Sentences ： Database management systems can be categorized according to the database model that they support, such as relational or XML, the type(s) of computer they support, such as a server cluster or a mobile phone, the query language(s) that access the database, such as SQL or XQuery, performance trade-offs, such as maximum scale or maximum speed or others. ;Sentences ： These drivers are code libraries that provide methods to prepare statements, execute statements, fetch results, etc. Examples include ODBC, JDBC, MySQL/PHP, FireBird/Python. ;Sentences ： Object DBMS (ODBMS) has transaction and storage components that are analogous to those in an RDBMS. ;Sentences ：;Sentences ： Codds Information Principle, which requires that all information in the database must be cast explicitly in terms of values in relations and in no other way.;Sentences ： Some of these extensions to the relational model integrate concepts from technologies that pre-date the relational model. ;Sentences ： Paradoxically, this allows products that are historically pre-relational, such as PICK and MUMPS, to make a plausible claim to be post-relational. ;Sentences ： Others have attacked the problem from the database end, by