Chapter 5 Database and Data Warehouse Unit 1 An Introduction to Database

Chapter 5 Database and Data Warehouse

Unit 1 An Introduction to Database

数据库系统的发展 第一个数据库系统诞生于 20 世纪 60 年代，其后，人们不断地开发数据模型（ Data model ），依次出现了表模型（ Table/flat model ）、层次模型（ Hierarchical model ）、网络模型（ Network model ）、关系模型（ Relational model ）和对象数据库模型（ Object database model ）。

Vocabulary

• flat/table model 平面 / 表模型• hierarchical model 层次模型• network model 网络模型• relational model 关系模型• DB (Database) 数据库• DBMS (Database Management Syste

m) 数据库管理系统

Vocabulary• dimension 维度• two-dimensional 二维的• array 数组• data element 数据元素• column 列• row 行• character 字符• integer 整数• floating point number 浮点数

Vocabulary• spreadsheet 电子表格• pointer 指针• reference 引用，参考• directed graph 有向图• undirected graph 无向图• data structure 数据结构• operator 操作符• relational algebra 关系代数• calculus 微积分

Vocabulary• constraint n. 约束• integrity constraints 完整性约束 更新数据库时，表中不能出现不符合完整性要

求的记录，以保证为用户提供正确、有效的数据。

三种完整性约束：1 、实体完整性2 、参照完整性3 、用户自定义完整性

Vocabulary• domain 域• attribute 属性• principle 原理• query n. 查询 ( 操作 ) v. 查询• mathematical 数学的• index n. 索引 v. 索引• sort n. 排序 v. 排序

Vocabulary• hash 散列表或哈希表，用于提高查询速

度的一种数据结构。• linked list 链表• map v. 映射，映象• SQL (Structured Query Language) 结构

化查询语言• polymorphism 多态性• search engine 搜索引擎

Text Historically, the hierarchical model was first achieved, followed by the network model, the relational model overcame with the so-called flat model accompanying it for low-end usage.

第 2 自然段第 4 行补充：

Answer the following questions according to paragraph 2

1. How to classify database?2. How many types can

database models be classified into? What are they?

3. Is flat model more advanced than relational model?

Answer the following questions according to paragraph 2

1. How to classify database?Answer: Use programming

model associated with database to classify them.

Answer the following questions according to paragraph 2

2. How many types can database models be classified into? What are they?

Answer: There are four types of database model: flat model, hierarchical model, network model and relational model.

Answer the following questions according to paragraph 2

3. Is flat model more advanced than relational model?

Answer: NO. “the relational model overcame

with the so-called flat model accompanying it for low-end usage.”

Text They were never theorized and were dee

med as data models only as a contrast to the relational model, not having conceptual underpinnings of their own; they have arisen simply out of the realization of physical constraints and programming, not data models.

Question: what does the word “they” refer to?They: hierarchical model; network model; flat model

Text

They were never theorized. They were deemed as data models only as a contrast to the relational model, not having conceptual underpinnings of their own.

Text

They were never theorized. v. 理论化它们从没得到理论化。

Text They were deemed as data models only as a contrast to the relational model, not having conceptual underpinnings of their own.deem ：认为 be deemed as : 把…视为…contrast ： n. 对比conceptual: adj. 概念的underpinning ： n. 基础，基础材料not having conceptual underpinnings of their own: 作为表示原因的状语，“它们没有自己的概念基础” They were deemed as data models only as a contrast to the relational model ：它们只有在与关系模型相比较时，才被视为数据模型。

Text They were deemed as data models only as a contrast to the relational model, not having conceptual underpinnings of their own. 由于它们没有自己的概念基础，它们只有在与关系模型相比较时，才被视为数据模型。

Text They were never theorized and were deemed as data models only as a contrast to the relational model, not having conceptual underpinnings of their own; they have arisen simply out of the realization of physical constraints and programming, not data models.

Text They have arisen simply out of the realization of physical constraints and programming, not data models.arise ： v. 上升，出现realization: n. 实现physical ： adj. 物理的constraint: n. 约束the realization of physical constraints and programming ：物理约束及编程的实现

Text

They have arisen simply out of the realization of physical constraints and programming, not data models.

它们只是简单地从物理约束及编程的实现中出现，而非数据模型。

Answer the following question according to paragraph 3

book_NO book_name author

publishing_house

publish_date

price

The following table records a set of attributes from a book information flat model, for each attribute or column, choose an adaptable data type.

(1) (2) (3) (4) (5) (6)

Answer the following question according to paragraph 3

book_NO book_name author

publishing_house

publish_date

price

(1) (2) (3) (4) (5) (6)

(1)Integer (2) character (3) character

(4) character (5) date

(6)floating point number

Network Model

Network model’s feature is that the schema, viewed as a graph in which object types are nodes and relationship types are arcs.

Relational Model

Translate the first paragraph in page 131.

Read the second paragraph in page 131.

According to the concept of each database model, which two models have pointers?

Answer: hierarchical model and network model

Text

As a result, relational databases can be used by multiple applications in ways (which) the original designers did not foresee, which is especially important for databases that might be used for decades.

Text

As a result, relational databases can be used by multiple applications in ways (which) the original designers did not foresee, which is especially important for databases that might be used for decades.

Text relational databases can be used by multiple applications in ...( 修饰词 )… ways

relational databases can be used by multiple applications:关系数据库能被多个程序使用in … ways ： 以…方式

关系数据库可以以…方式被多个程序使用。

Text relational databases can be used by multiple applications in ways (which) the original designers did not foreseeoriginal: 原始的，初始的original designer - 》 database designerforesee: 预见，预见到(which) the original designers did not foresee ：数据库设计者没有预见到的ways (which) the original designers did not foresee ：数据库设计者没有预见到的方式

Text

relational databases can be used by multiple applications in ways (which) the original designers did not foresee.

关系数据库可以以数据库设计者没有预见到的方式被多个程序使用。

Text As a result, relational databases can be used by multiple applications in ways (which) the original designers did not foresee, which is especially important for databases that might be used for decades.which --> > relational databases can be used by multiple applications in ways (which) the original designers did not foresee“which” 指的是关系数据库的这种性质：“关系数据库可以以数据库设计者没有预见到的方式被多个程序使用。”

Text

As a result, relational databases can be used by multiple applications in ways (which) the original designers did not foresee, which is especially important for databases that might be used for decades.

which is especially important for databases that might be used for decades

is especially important for databases ： 对数据库来说是十分重要的database that might be used for decades: 可能被用上数十年的数据库

which is especially important for databases that might be used for decades ：对可能被用上数十年的数据库来说是十分重要的

As a result, relational databases can be used by multiple applications in ways (which) the original designers did not foresee, which is especially important for databases that might be used for decades.

因此，关系数据库可以以数据库设计者没有预见到的方式被多个程序使用，这对于可能被用上数十年的数据库来说是十分重要的。

Fill in the blanks with the following words

A. query B. database C. DBMS D. accessing E. interface The system software package that handles the difficult tasks associated with creating, __(1)_, and maintaining database records is called _(2). It establishes an _(3)_ between the database itself and the users of the database. It can organize, process and present selected data elements from the _(4)_. This capability enables decision makers to search and _(5)__ database contents in order to find answers to unplanned questions.

Implementations and Indexing

Read the first paragraph in this section andfill in the blanks with the following words in

proper form. A. row B. pointer C. content D. index E. query D. table• Indexing is a way to increase the _(1)_

speed in a database. The function of index is just like a _(2)_ in a book. If you want to find certain records in a _(3)_, _(4)_ can help you quickly navigate to the _(5)_ that match the values you specify, because it associates the _(6)_ in it with those values.