《现代数据库管理(英文版)》课件—14

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现代数据库时态数据库PPT课件

（2）有效时间有效时间（Valid Time）是指一个对象（事件）在现实世界中发生并保持的那段时间，或者该对象在现实世
界中为真的时间。既可以反映过去和现在的时间，还可以反映将来的时间。有效时间的含义依赖于具体应用，取值是否有效视具体应用场合而定，对应于实际应用的需要或现实世界变化的历史，比如身份证，教师的职称等。和用户定义的时间不同，当查询语句被检测到有时态语义的时候，有效时间是由数据库系统解释的。而且有效时间可以被更新，有效时间的提供和更新也是由用户来完成的。
姓名李小山
张又宝
出生年月
196009
职称讲师
196411
副教授教授
工资
有效时间
1000 1300
1700 2100
(199809，199903) (199904，now)
(199803，200003) (200004，now）
姓名李小山
张又宝
出生年月 196009
职称
讲师副教授
196411
第6页/共53页
• 3、目前时态数据库研究取得了相当的进展，但是大多研究局限在数据库的时态属性，而忽视了其他信息的时态属性。时态数据技术目前还停留在“数据”处理上，关于时态逻辑和推理方面的研究，主要优点是符号演算和推理能力强，但是信息处理能力弱，与时态数据库和时态信息处理研究相脱离。关于时态知识与逻辑方面主要包括时间区间逻辑运算的扩充等，没有涉及时态知识数据库模型。
有效时间维 Now
Now
事务时间维
第14页/共53页
6.6.2 回滚数据库
•
回滚数据库(Rollback Database)支持事务时间，它按事务时间进行编址，
保存了过去每次事务提交，状态演变之前的状态，是数据库事务变化的时间轴。

数据库系统原理英文PPT课件

file system: file’s logical structures and access methods
I/O system : drivers
memory controllers (i.e. disk controller),
on the basis of secondary storage’s physical structures, such as storage structures, access method
February 2011
7
第7页/共70页
§1.2 Purpose of Database Systems (cont.)
• Data management on the basis of file systems
• Example
— customer_record=<c_name, c_id, street, city> in Customer_File
February 2011
1
第1页/共70页
§1.0 DB, DBMS, DBS
• Definitions in the textbook • Database (DB) — a collection of interrelated data, stored in systems as files • Database management system (DBMS) — DB, or a collection of interrelated data — set of programs to access the data in DB
• Databases and DBS touch all aspects of our lives • Banking: all transactions • Airlines: reservations, schedules • Universities: registration, grades • Sales: customers, products, purchases • Manufacturing: production, inventory, orders, supply chain • Human resources: employee records, salaries, tax deductions

数据库管理系统[]PPT课件

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3 MySQL
MySQL是最流行的开发源码SQL数据库管理系统，他是有MySQL AB公司开发、发布并支持。
开放源码：意味着任何人都能使用和改变软件；任何人都能从INTERNER下载软件，无需支付任何费用。
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4 Microsoft SQL Server
目前， Visual FoxPro已经成为高等学校、各类培训非信息系统专业学生数据库技术介绍的首选软件。
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6 Microsoft Access
Microsoft Access作为Microsoft office 组件之一，是在windows环境下非常流行的桌面型数据库管理系统。
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4 结构清晰
数据库管理系统是一个复杂的系统软件，涉及面广，包括向上与用户接口，向下与操作系统、软件硬件资源的接口。
因此，应该使数据库管理系统内部结构清晰，层次分明，便于自身设计、开发和维护，以及支持外层开发环境的构造。
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5 开放性
系教研室
学生
老师
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网状模型
学生
课程
选课
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关系模型
第一个基于关系模型的商业产品时 1980年左右Oracle公司和IBM公司出品的Oracle和DB2。
第一个成功的微机数据库产品是运行于CP/M,PC-DOS,MS-DOS操作系统上的dBASE。

英文数据库课件

1.2
Chapter 1 Introduction
1.1 Evolution of Database Management Systems 1.2 Levels of Abstraction 1.3 Data Models 1.4 Components of Database Management Systems
Degree
Credit Academic Division
Adress
Property Division
1.11
2) Database Systems
Advantages of using a DBMS to manage data:
Data independence
Provide an abstract view of data to hide the details of
1.4.1 Data Definition Language 1.4.2 Data Manipulation Language
1.4.3 Database Users
1.4.4 Database Administrator
1.4.5 Transaction Management
1.4.6 Storage Management
File Systems
Database Systems
1.5
1）File Systems
program 1
data 1
program 2
file systems
data 2
program n
data n
1.6
Example
Treasury
Sno Sname Department Allowance

《现代数据库管理(英文版)》课件—15

connects to a class
Multiplicity:
How many objects participate in an association. Lower-bound…Upper-bound (cardinality)
9
Figure 13-3 Examples of association relationships of different degrees
Behavior is expressed through operations that can be performed on it
Identity: every object has a unique identity, even if all of its attribute values are identical to another object’s
5
Figure 13-2 UML class and object diagram a) Class diagram showing two classes
Class diagram shows the static structure of an objectoriented model: object classes, internal structure, relationships
Tangible: person, place or thing Concept or Event: department, performance,
marriage, registration Artifact of the Design Process: user interface,
controller, scheduler

《管理信息技术》ppt课件(英文版)—

Chapter 13
Benefits and Costs - Other measures
Distinguishing between investments in infrastructure and investments in specific applications will assist the analysis. IT infrastructure, provides the foundations for IT applications in the enterprise (data center, networks, date warehouse, and knowledge base) and are long-term investments shared by many applications throughout the enterprise. IT applications, are specific systems and programs for achieving certain (payroll, inventory control, order taking) objectives and can be shared by several departments, which makes evaluation of their costs and benefits complex.
present value of the future benefits to the cost required to achieve
those benefits.
•
Return on investment ( ROI) measures the effectiveness of

管理信息系统双语课件

7
管理信息系统双语——总复习 Systems from a Constituency Perspective: ★ ★ ★
Transaction Processing Systems(TPS), Management Information Systems(MIS),
管理信息系统
Decision-Support Systems(DSS), Executive Support Systems(ESS)
4. Types of Business Information Systems
Systems for Functional Perspective: Sales and Marketing Systems, Manufacturing and Production Systems, Finance and Accounting Systems, Human Resources Systems
5. Enterprise Applications: ★ ★ ★ ★ ★
Enterprise Systems Supply Chain Management Systems Customer Relationship Management Systems Knowledge Management Systems
13
管理信息系统双语——总复习 7. push-based model, pull-based model ★ ★ 8. Supply chain planning systems, supply chain execution 管理信息系统 systems ★ ★ 9. CRM Systems capture and integrate customer data from all over the organization, consolidate the data, analyze the data, and then distribute the results to various systems and customer touch points across the enterprise. 10. cross-selling, up-selling, bundling ★ ★ 11. churn rate★ ★

中职计算机专业英语教学课件Lesson 14 Database

3
Lesson 14 Database
A database is quite helpful for people. For both individuals and organizations, there are many advantages to having databases. For example, a shopkeeper can use a database system to keep an inventory of his stores and get a very clear idea about what sells well. Additionally, he can see how much he earn each day and how much stock he has got. A director of a large company can keep data of his employees in a database to manage the staff. A database system can also help a hotel receptionist to keep record of reservations of rooms. She can arrange the check-in and check-out of customers accordingly.
第三阶段（20世纪90年代），其产品加强了数据完整性和安全性。完整性的控制在核心层实现，克服了在工具层的完整性可能存在“旁路”的弊病。目前小型数据库系统有Foxpro, Access, PARADOX等，大型数据库系统有DB2, INGRES, ORACLE, INFORMIX, SYBASE, SQL SERVER 等。

管理信息系统(英文版第7版)延伸课件kroenke_emis7e_inppt_ce14

Chapter Extension 14
Data Breaches
Study Questions
Q1: What is a data breach? Q2: How do data breaches happen? Q3: How should organizations respond to data breaches? Q4: What are the legal consequences of a data breach? Q5: How can data breaches be prevented?
Copyright © 2017 Pearson Education, Inc.
ce14-2
Q1: What is A Data Breach?
• Data breach – Unauthorized person views, alters, or steals secured data
• 1+ billion people affected in past 5 years, 75% of breaches happened in US
• Rogue internal employees • Credit card fraud, identity theft, extortion, industrial espionage
Copyright © 2017 Pearson Education, Inc.
ce14-7
Q2: How Do Data Breaches Happen?
Indirect Costs • Loss of reputation • Abnormal customer turnover • Increased customer acquisition activities • Additional $3.3 million per incident in US

管理学]管理信息系统英文版课程及答案PPT课件

• A business model includes how a company produces, delivers, and sells its products and services
• The music industry has seen drastic changes in business models in recent years
❖ Solutions: MLB Web sites and cell phone ticketing enable electronic ticketing and delivery of online information and games, which increase sales.
Major League Baseball Hits a Home Run with Information Systems（continue）
• In 2005, more wireless phone accounts were opened than telephone land lines installed
• More than 35 million people receive their news online; 32 million Americans read blogs
❖ 理念：创始人沃尔顿先生倡导的尽量降低经营成本，实行低价销售。
宗旨：帮顾客节省每一分钱。
口号：天天平价，始终如一。
1995年经营成本占销售额的15.8%（世界上大多数零售商的经营成本在40%以上）
❖ 手段：拥有世界上最大的私有卫星系统，与3800家供货商实现计算机联网。总部的计算机系统与16个发货中心以及1000多家商店连接，做到即时销售，大大压缩产品时间成本，减少库存风险，加速资金周转。

《数据库管理》PPT课件 (2)

余额 8700 4500
事务
性质3：隔离性(Isolation)
如果多个事务并发执行，应像各个事务独立执行一样，互不干扰
由DBMS的并发控制子系统实现 /*事务T1*/ UPDATE 账户 SET 余额=余额 -100 WHERE 账号=‘A’ 执 UPDATE 账户 SET 余额=余额+100 行 WHERE 账号=‘B’ 的时间顺序 UPDATE 账户 SET 余额=余额+100 WHERE 账号=‘B’
封锁技术
共享锁(S锁，Shared lock) 如果事务T对某数据加上S锁后，仍允许其他事务再对该数据加S锁，但在对该数据的所有S锁都解除之前，决不允许任何事务对该数据加X锁 S锁有加锁、解锁和升级三种操作如果事务T获得数据R上的S锁，则T可读但不可写R S锁用于SELECT等非更新数据的操作
可重复读
T1
T2
SLOCK A，B 获得
读A＝50，B＝100
求和＝150
XLOCK B 等待
读A＝50，B＝100 等待
求和＝150
等待
COMMIT
等待
UNLOCK A，B
等待
获得XLOCK B
读B＝100
B＝B＊2
写回B＝200
COMMIT，UNLOCK B
封锁协议
上述三种封锁协议的主要区别在于什么操作需要申请封锁，以及何时释放锁（即持锁时间）
封锁技术
封锁类型的相容矩阵
其他事务拥有的锁
无锁 S锁
X锁
加锁请求
S锁
Y
Y
N
X锁
Y
N
N
Y－相容的请求，N－不相容的请求
封锁协议

现代数据库系统41页PPT

谢谢你的阅读
❖ 知识就是财富 ❖ 丰富你的人生
71、既然我已经踏上这条道路，那么，任何东西都不应妨碍我沿着这条路走下去。——康德 72、家庭成为快乐的种子在外也不致成为障碍物但在旅行之际却是夜间的伴侣。——西塞罗 73、坚持意志伟大的事业需要始终不渝的精神。——伏尔泰 74、路漫漫其修道远，吾将上下而求索。——屈原 75、内外相应，言行相称。——韩非
1、不要轻!整个生命就是一场冒险。走得最远的人，常是愿意去做，并愿意去冒险的人。“稳妥”之船，从未能从岸边走远。-戴尔．卡耐基。
梦境
3、人生就像一杯没有加糖的咖啡，喝起来是苦涩的，回味起来却有久久不会退去的余香。
现代数据库系统 4、守业的最好办法就是不断的发展。 5、当爱不能完美，我宁愿选择无悔，不管来生多么美丽，我不愿失去今生对你的记忆，我不求天长地久的美景，我只要生生世世的轮回里有你。

《现代数据库管理(英文版)》课件—11

2
Traditional Administration Definitions
Data Administration: A high-level function
that is responsible for the overall management of data resources in an organization, including maintaining corporate-wide definitions and standards
Integrity Controls
Protect data from unauthorized use Domains–set allowable values Assertions–enforce database conditions Triggers – prevent inappropriate actions, invoke
10
Figure 11-3 Establishing Internet Security
11
Web Security
Static HTML files are easy to secure
Standard database access controls Place Web files in protected directories on server
Database Administration: A technical
function that is responsible for physical database design and for dealing with technical issues such as security enforcement, database performance, and backup and recovery

《现代数据库管理(英文版)》课件—03

Generalization: The process of
defining a more general entity type from a set of more specialized entity types. BOTTOM-UP
Specialization: The process of defining
Note: no subtype for motorcycle, since it has no unique attributes
11
Figure 3-5 Example of specialization a) Entity type PART
Only applies to manufactured parts Applies only to purchased parts
21
Figure 3-9 Subtype discriminator (overlap rule)
22
Figure 3-10 Example of supertype/subtype hierarchy
23
Entity Clusters
EER diagrams are difficult to read when there are too many entities and relationships
Total Specialization Rule: Yes (double line) Partial Specialization Rule: No (single line)
14
Figure 3-6 Examples of completeness constraints a) Total specialization rule

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Chapter 13 (Online): Object-Oriented Data
Modeling
Modern Database Management 10th Edition
1
Objectives
Define terms Describe phases of object-oriented development life
Class Object Association Inheritance of
attributes
Inheritance of behavior
EER
Entity type Entity instance Relationship Inheritance of
attributes
No representation of behavior
3
Figure 13-1 Phases of object-oriented systems development cycle
Progressive and iterative development process
4
OO vs. EER Data Modeling
Object Oriented
Behavior is expressed through operations that can be performed on it
Identity: every object has a unique identity, even if all of its attribute values are the same
composition Specify types of business rules in a class diagram
2
What Is Object-Oriented Data Modeling?
Centers around objects and classes Involves inheritance Encapsulates both data and behavior Benefits of Object-Oriented Modeling
9
Operation
A function or service that is provided by all instances of a class
Ability to tackle challenging problems Improved communication between users, analysts,
designers, and programmers Increased consistency in analysis, design, and
8
Figure 13-2 UML class and object diagram (cont.) b) Object diagram with two instances
Object diagram shows instances that are compatible with a given class diagram
7
Figure 13-2 UML class and object diagram a) Class diagram showing two classes
Class diagram shows the static structure of an objectoriented model: object classes, internal structure, relationships
Object-oriented modeling is typically represented using the Unified Modeling Language (UML)
5
Classes and Objects
Class: An entity that has a well-defined role in the application domain, as well as state, behavior, and identity
Object: a particular instance of a class
Objects exhibit BEHAVIOR as well as attributes Different from entities
6
State, Behavior, Identity
State: attribute types and values Behavior: how an object acts and reacts
programming Explicit representation of commonality among system
components System robustness Reusability of analysis, design, and programming results
Tangible: person, place or thing Concept or Event: department, performance,
marriage, registration Artifact of the Design Process: user interface,
controller, scheduler
cycle State advantages of object-oriented modeling Compare object-oriented model with E-R and EER
models Model real-world application using UML class diagram Provide UML snapshot of a system state Recognize when to use generaliz