Chapter 12 DATABASES

Chapter 12

DATABASES

      Through this article we may understand many information about the database.In fact, I also understood from the internet to about the database.The database is defers to the construction of data to organize, the memory and the managerial data warehouse, it produced is 50 years ago, along with information technology and market development, specially after in the 1990s, the data management no longer merely was the memory and the managerial data, but transformed each data management way which the user needed. The database has many types, the memory had each kind of data form from the simple to be able to carry on the large-scale database system which the mass data saved in each aspect to obtain the widespread application.

Introduction　　                                                                                       

Strictly speaking, the database is “organizes, the memory and the managerial data warehouse according to the construction of data”. In management of economy's routine work, needs to admit frequently certain related data such “the warehouse”, and needs to carry on corresponding processing according to the management. For example, the enterprise or Institution's Personnel must this unit staff's basic situation (staff number, name, age, sex, native place, wages, resume and so on) deposit frequently in the table, this table may regard as is a database. Had this " Data warehouse " We may according to need momentarily to inquire some staff's basic situation, may also inquire the wages in some in scope staff population and so on. If these work can carry on automatically on the computer, then our personnel management may achieve the extremely high level. In addition, in the financial control, the storage management, production management also needs to establish numerous this kind of " Database " , enables its to be possible to realize financial, the warehouse, the production automated management using the computer.And the database is defers to some kind of data model to organize and deposits in the second-level memory's data acquisition. This kind of data acquisition has following characteristic: It is not as far as possible redundant, serves take the most superior way as some specific organization's many kinds of applications, its construction of data independence in uses its application procedure, increases to the data, deletes, changes with the retrieval by unifies the software to carry on the management and the control. Looked from the development history that the database is the data management higher phase, it is develops by the document management system.So the database is a long-term memory in the computer, organized, has sharing, the global administration data acquisition.

In database data nature

1. data integrity: The database is a unit perhaps an application domain conventional data processing system, what he saves is belongs to the enterprise and the enterprise department, the association and individual related data set. In the database data is embarks the establishment from the total view, he carries on the organization, the description and the memory according to certain data model. Its structure based on data natural connection, thus may provide all essential access path, and the data no longer aims at some application, but faces the entire organization, has the whole structurized characteristic. 　

　

2 data sharing: In the database data is shares its information for the numerous users to establish, already got rid of the concrete program limit and the restriction. The different user may according to the respective usage use database in data; Many users may simultaneously share in the database the data resources, namely the different user may in the simultaneous access database identical data. Not only data sharing has satisfied various users to the information content request, simultaneously has also satisfied between various users the message communication request.

DBMS Structure

   We knew that DBMS is designed and in logic constructs or the data which arranges is used together.DBMS Structure may divide into 5 kinds is:Hierarchical DB, Network DB, Relational DB, Multidimensional DB, OODB

   The hierarchical structure model materially is one kind has the root node directional ordered tree (in mathematics " Sets up " By the definition is the connection chart which not returns). The next chart is a College organization structure drawing. This organizational structure image tree, the school is the tree root (is called root node), each is, the specialty, the teacher, the student and so on (is called point) for a spot, side tree root's is called with spot between contacting, the tree root ratio of with the side is 1:N, namely the tree root only then, the branch has N.

The Network database is called the netted database system according to the lattice construction of data establishment's database system, its typical representative is DBTG (Data Base Task Group). May transform with the mathematical method the lattice construction of data as the level construction of data.

 The relational database is a database system which is composed of the relations construction of data is called the relational database system.The relationship construction of data sums up some complex construction of data as the simple binary relation.In the relational database, establishes nearly completely to the data operation in or many relational forms, through to these relational operations and so on form's classification, merge, connection or selection realizes the data management.

  The Object-oriented is one understanding methodology, is also one new programming methodology. Unify the object-oriented method and the data bank technology may cause the database system's analysis, the design greatest degree with the people to the objective world understanding consistent. The object-oriented database system is to satisfy the new generation database system which the recent database application needs to produce.

 The Multidimensional Database may the understanding be simply: Stores the data in a n Uygur array, but is not form depositing which relational database such records likely. Therefore it has the massive sparse matrices, the people may through the multi-dimensional view observed data. The multi-dimensional database increased a time Uygur, compares with the relational database, its superiority lies in may raise the data processing speed, speeds up the reaction time, raises the inquiry efficiency.

Website database safe hidden danger

Causes the reason which the security problem exists to cause the electronic commerce website database existence safe hidden danger the reason mainly to display at present in the following several aspects:

(1)    the user is not correct to the database visits, causes the database data mistake;

(2)    for some kind of goal, destroys the database intentionally, enables it to restore;

(3)    the illegal visit should not visit database information, but not scar;

(4)    the user when carries on the database visit through the network, has the possibility receives each kind of technology (for example wiretapping and so on) attack;

(5)    the illegal user bypasses the security kernel, steals phenomena and so on information resource; (6) without authorization the illegal revision database data, cause its data to lose authenticity and some one. 

Chapter 11 INFORMATION SYSTEMS

Chapter 11  INFORMATION SYSTEMS

Definition

Information Systems (IS) is an academic/professional discipline bridging the business field and the well-defined computer science field that is evolving toward a new scientific area of study.An information systems discipline therefore is supported by the theoretical foundations of information and computations such that learned scholars have unique opportunities to explore the academics of various business models as well as related algorithmic processes within a computer science discipline.

Information systems are implemented within an organization for the purpose of improving the effectiveness and efficiency of that organization. Capabilities of the information system and characteristics of the organization, its work systems, its people, and its development and implementation methodologies together determine the extent to which that purpose is achieved.

Information Systems support the natural flow of information within an organization’s structure:

1.   5 Functions

.. Accounting- is the process of communicating financial information about a business entity to users such as shareholders and managers.

.. Marketing- is the activity, set of institutions, and processes for creating, communicating, delivering, and exchanging offerings that have value for customers, clients, partners, and society at large.

.. Human Resources- is a term used to describe the individuals who make up the workforce of an organization, although it is also applied in labor economics to.

.. Production- is a computer program typically used to provide some form of artificial intelligence, which consists primarily of a set of rules about behavior.

.. Research- the search for knowledge, or as any systematic investigation, with an open mind, to establish novel facts, usually using a scientific method

2.         Management Levels

So the management levels have three type, the information is in the picture.

3.      Information Flow

In discourse-based grammatical theory, information flow is any tracking of referential information by speakers. Information may be new, just introduced into the conversation;, already active in the speakers' consciousness; or old, no longer active. The various types of activation, and how these are defined, are model-dependent.

Information flow affects grammatical structures such as

• word order (topic, focus, and afterthought constructions).
• active, passive, or middle voice.
• choice of deixis, such as articles; "medial" deictics such as Spanish ese and Japanese sore are generally determined by the familiarity of a referent rather than by physical distance^{[citation needed]}.
• overtness of information, such as whether an argument of a verb is indicated by a lexical noun phrase, a pronoun, or not mentioned at all.

Computer-based Information Systems

TPS- A transaction processing system is a type of information system. TPSs collect, store, modify, and retrieve the transactions of an organization. A transaction is an event that generates or modifies data that is eventually stored in an information system.

                    Accounting Activities TPS

 MIS- A management information system (MIS) is a system that provides information needed to manage organizations effectively. Management information systems are distinct from regular information systems in that they are used to analyze other information systems applied in operational activities in the organization

  DSS- A decision support system (DSS) is a computer-based information system that supports business or organizational decision-making activities. DSSs serve the management, operations, and planning levels of an organization and help to make decisions, which may be rapidly changing and not easily specified in advance.

Typical information that a decision support application might gather and present are:

• inventories of information assets (including legacy and relational data sources, cubes, data warehouses, and data marts),
• comparative sales figures between one period and the next,
• projected revenue figures based on product sales assumptions

Chapter 10 Privacy and Security

Chapter 10  Privacy and Security

  Privacy is the ability of an individual or group to seclude themselves or information about themselves and thereby reveal themselves selectively.

It’s three types of:

1.         Accuracy is about responsibility of those who collect data.

2.         Property is any physical or intangible entity that is owned by a person or jointly by a group of people.

3.         Access is responsibility of those who control data and use of data

Security

Computer crime, or cybercrime, refers to any crime that involves a computer and a network, where the computers may or may not have played an instrumental part in the commission of a crime.

1.         Viruses infect computers or other electronic devices and are passed on by user activity, for example by opening an email attachment

2.         Worms self-propagate using an internet connection to access vulnerabilities on other computers and to install copies of themselves.

3.         Trojans are malware masquerading as something the user may want to download or install, that may then perform hidden or unexpected actions, such as allowing external access to the computer.

How to precaution the computer crime?

v  Get Safe Online

The Government–industry partnership education initiative Get Safe Online’ is the first national internet-based computer security awareness campaign for the general　public and small businesses.

v  Technological solutions

A range of technologies is available to home users and organizations to secure their computers．

Other Hazards

1.         Natural hazards include fires, floods, winds, hurricanes, etc., keep data is safe locations in case of fire or storm damage

2.         Civil strife – wars, riots, etc. are real risks

3.         Technological failures – voltage surges or spikes (key term); hard disk crashes possibly occur when the hard disk is bumped

4.         Human errors – data entry are commonplace mistakes; programming, faulty design mistakes; sloppy procedures

In Malaysia

  In Malaysia, the Parliament amended the provisions of punishments for certain white-collar offences on 17 September 1993. Offences of criminal breach of trust under sections 406 to 409 and cheating under　section 420 of the Penal Code now carry a mandatory minimum term of imprisonment (one year) together with mandatory whipping, and the courts have the discretion to further impose a fine.

The Royal Malaysia Police, through its Commercial Crime Investigation Department (CCID), is the main agency that investigates white-collar crime cases in Malaysia. Over the years, the police have successfully investigated, arrested and prosecuted most of the criminals involved in the cases reported to them.

Conclusion

The fundamental issue in most computer crime is the criminals' lack of respect for the property or privacy of other people. I hope that society will recognize the seriousness of computer crime and demand more severe punishment for such criminals.

Chapter 9 Communications and Networks

Chapter 9 Communications and Networks

Communication Systems

Four basic elements

1.         Sending and receiving devices

2.         Communication channel

3.         Connection devices

4.         Data transmission specifications

Physical Connections

•          Ethernet cable - consists of twisted pair cable; slowest; being phased out by more advanced and reliable media

•    Coaxial cable – single solid copper core; 80 times transmission of twisted pair; television and computer networks

•          Fiber optic – 26,000 times capacity of twisted pair cable; more secure and reliable; best over limited distances; lighter, more reliable, and less expensive than coaxial cable

Types of wireless connections are:

•    Infrared

•    Light waves used over short distances

•    Sometimes called line of sight communications

•    Sending and receiving devices must be in clear view of one another

•    Broadcast radio

•    Uses towers called transceivers (key term)

•    Web-enabled devices follow a standard known as Wi-Fi (wireless fidelity)

•    Microwave

•    Uses high-frequency radio waves

•    Also line of sight

•    Used for short distances

•    Satellite uses satellites orbiting about 22,000 miles above the earth as microwave relay stations; many of these offered by Intelsat, the International Telecommunications Satellite Consortium which is owned by 114 governments and forms a worldwide communications system

•    Satellites can be used to send and receive data; Uplink is sending data to satellite and Downlink refers to receiving data from a Satellite

•    GPS (Global Positioning system)  use a network of 24 satellites owned and managed by the Defense Department which continuously sends location information to earth

Networks

A computer network is a communication system that connects two or more computers so that they can exchange information and share resources.

The types of computer networks:

•    Node – any device connected to a network

•    Client – a node that requests and uses resources available from other nodes

•    Server – a node that shares resources with other nodes; dedicated servers  specialize in performing specific tasks—could be an application server, communication server, database server, file server, printer server, or Web server

•    Directory server – a specialized server that manages resources such as user accounts for an entire network

•    Host – large centralized computer

•    Switch – the center or central node for other nodes; previously done by something called a hub

•    Network interface cards (NIC) – connects the computer to a network

•    Network operating system (NOS) – software to control and coordinate activities between computers on a network

•    Network administrator – a computer specialist; network administrator

Chapter 8 Secondary Storage

Chapter 8 Secondary Storage

The storage have two kind of:

1.       Secondary storage: sometimes called auxiliary storage, is all data storage that is not currently in a computer's primary storage or memory. An additional synonym is external storage. 

2.       Primary storage:  (or main memory or internal memory), often referred to simply as memory, is the only one directly accessible to the CPU. The CPU continuously reads instructions stored there and executes them as required. Any data actively operated on is also stored there in uniform manner.

Secondary storage:

–    Nonvolatile storage

–    Permanent storage

Secondary Storage Devices

•    Optical disks – large storage capacity (Key Term)

•    Hard disk – large storage capacity and fast retrieval times