BEC-Chapter 4 Appendix
Disadvantages of DBMS
1. Cost-expensive 2. Highly Trained Personnel are Necessary 3. Increased Chances of Breakdowns 4. Possible Obscuring of the Audit Trail 5. Specialized Backup and Recovery Procedures Required
Major Uses of a DBMS (4 functions)
1. Database Development: database administrator uses DBMS to create a new, empty database. 2 Database Query: the end users can retrieve specific data or information from the database. 3. Database Maintenance: updating the DBMS software and the revision of the database structure to reflect new business needs. 4. Application Development: DBMS allow a DBA or computer programmer to use a programming language or a series of macros to "turn a database into a computer software application" The database can be automated and converted into an application made up of user-friendly screens.
Types of Application Software
1. Licensing the Use of Software: purchasing software means purchasing the license to use the software under certain prescribed terms and conditions. 2. Escrowing of the Source Code: if application software is acquired from an outside vendor, the organization acquiring the application may or may not obtain access to the source code. Escrow of the source code supposedly protects the purchaser if the outside vendor fails to live up to its contractual obligations 3. Groupware (group working software): is software that lets different people work on the same documents and coordinate their work activities.
Components of LANs
1. Node: any device connected to a network 2. Workstation: is a node, usually a PC, that is operated by end user 3. Server: a node dedicated to providing services or resources to the rest of the network (i.e. a printer server provides access to high-quality printers) 4. Network Interface Card (NIC): a circuit board installed on a node that allows the node to connect with and communicate over the network.
Types of Databases
1. Operational Databases: store detail data needed to support the day-to-day operations 2. Analytical Databases: store data and info extracted from operational databases. (summarized data) 3. Data Warehouses: store data from current and previous years, often from both operational and analytical databases 4. Distributed Databases: physically distributed in some manner on different pieces of local or remote hardware. 5. End-User Databases: developed by end users at their workstations. (ex: email or downloads from the internet)
Advantages of DBMS
1. Reduction of Data Redundancy and Inconsistency 2. Potential for Data Sharing 3. Data Independence 4. Data Standardization 5. Improved Data Security 6. Expanded Data Fields 7. Enhanced Info timeliness, Effectiveness, and Availability.
Access Log
A file with info about each access to a file or website. They provide some security but only if the logs are periodically reviewed and unusual activity is investigated.
Storage Are Network (SAN)
A network that contains remote storage devices (disk arrays, tape libraries, and CD arrays) to servers in such a way that the devices appear to the operating system to be local devices.
Wi-Fi Standards
A set of standards for wireless LANs. Equipment that uses the standard often can interfere with microwave ovens, cordless telephones, and other equipment using the same frequency. Wi-Fi is a wireless form of Ethernet.
Single Log-in
A system that allows a user who utilizes several different systems the ability to log in to them all with one user ID and one password.
Wi-Fi Protection Access Standard
An industry standard specifying security mechanisms for Wi-Fi. It supersedes the previous security specification called WEP (wired equivalent privacy). The Wi-Fi protected access standard provides for an encryption key that is longer and is changed periodically.
Network Topologies: Ring Networks
Are formed in a ring with each device connected two other devices. Signals are transmitted in the form of messages that are transmitted to and are received by all of the devices sequentially, but only the intended device actually accepts and process the message If any of the devices in a ring topology are down, the entire network is down.
Network Topologies: Star Networks
Are formed in a star with each device connected to a central "hub." The hub controls the transmission. If any of the devices are down, only that device is down; if the hub is down, the entire network is down. Ex. Telephone systems connected to a PBX and many home networks
Wireless Networking Devices Standard
Can operate in two modes: infrastructure mode and ad hoc mode. Infrastructure mode anticipates networking devices communicating through an access point. Ad hoc mode anticipates that networking devices are physically close enough that they can communicate without the access point.
Peripherals
Devices that transfer data to or from the CPU but that do not take part in the actual processing the data 1. Input Devices: supply the data to be processed 2. Output Devices: transfer data from the processing unit to various output media
Protocol
File transport protocol: a network protocol used to exchange files. Simple Mail transfer protocol (SMTP): a protocol for transmitting text-based e-mail. SMTP provides outbound, not inbound, mail transport. Simple Network Management Protocol (SNMP): is a protocol for monitoring a network. IN SNMP, a piece of software called an agent runs on each of the devices being monitored and reports info to the network management/monitoring system
Getaways and Routers
Gateway is a combo of hardware and software that connect different types of networks by translating from one set of network protocols to another. Router is used to route packets of data through several interconnected LANs or to a WAN Bridge is used to connect segments of a LAN which both use the same set of network protocols.
Communication/ Network Protocols
In order to transmit information from one place to another, a telecommunications network must perform the following functions: 1. establish an interface between the sender and the receiver 2. transmit the info 3. Route messages along the various paths the info might travel 4. check for transmission errors 5. Convert messages from one speed or transmission format to another
Application Software
Includes the diverse group of systems and programs that an organization uses to accomplish its objectives. It can be generic ( work processors, spreadsheets, database or accounting systems) or custom developed.
Client/Server Configurations
Most LANs (and WANs) are set up as client/server configurations. Other processors that provide services to the workstations are called serves. The workstations send requests for data and other services to the servers.
Bluetooth Standard
Networking standard for small personal are networks (PAN). Bluetooth can be used to connect up to eight devices within a 100-meter radius, depending on the power of the transmission are using low-power radio-based communication.
Value Added Networks (VANs)
Privately owned and managed communications networks that provide additional services beyond standard data transmission. VANs are often used for electronic data interchange (EDI). VANs: 1. provide many additional services, including automatic error detection, protocol conversion, and message storing and forwarding 2. provide good security because they are private networks 3. often batch transactions and send them at night when line traffic is lower 4. Messages are separated by vendor, batched together, and transmitted to their specific destinations. 5. Normally charge a fixed fee plus fee per transaction and can be prohibitively expensive for smaller companies.
Referential Integrity
Referential integrity in DBMS prevents customers records from being deleted and destroying the relationship to the invoices (customer records{tables} and invoice records {tables})
Relational Technology
Relational-meaning the data is stored in 2-dimensional tables that are related to each other via keys, Relational databases of en include ad hoc report writers
Network Topologies: Bus Networks
Use a common backbone to connect all the devices on the network. Signals are transmitted over the backbone in the form of messages that are transmitted to and are received by all the devices, but only the intended device actually accepts and processes the messages; the other devices ignore the message. Backbone: that part of a network that carries the major portion of the network traffic.
Wireless networks: security risks
Wireless access is convenient and easy, but provide another venue for attack and extends the perimeter that must be protected.
File
a collection of related records, often arranged in some kind of sequence, such as a customer file made up of customer records and organized by customer number
Access Point
a device that connects wireless communication devices together to form a wireless network. Usually called a wireless access point (WAP). The access point normally connects to a wired network but could also be a simple as a smart phone serving as an access point (hot spot).
Field
a group of bytes in which specific data element such as an employee number or name is stored
Record
a group of fields that represents the data that is being stored for a particular entity such as a customer or an account receivable
Network
a group of interconnected computers, terminals, communications channels, communications processors, and communication software.
Byte
a group of normally 8 bits that can represent a number or a letter, with the specific form dependent on what internal representation format is being used.
Ethernet
a large collection of frame-base networking technologies for LANs. It incorporates a number of wiring and speed standards for the physical layer and a common addressing and message format.
Bandwidth
a measure of a communication medium's info carrying capacity.
Wide Are Networks (WANs)
allow national and international communications, They usually employ nondedicated public communications channels (satellite) as their communications media. WAN communication services may be provided by value added networks, internet-based networks, or point-to-point networks
Programming Languages
allow programmers to write programs in source code. 1. Fourth-Generation Language: are languages that enable end users to develop applications with little or no technical assistance. 2. Object-Oriented Programming: combines the data and the specific procedures that operate on that data into one thing called an object. It's intended to produce reusable code 3. Debugging: is the process of finding errors in computer programs and correcting them.
Network Topologies: Tree Networks
connect multiple stars into a bus. Each hub is connected to the bus and handles the transmission for its star.
Network Topologies
defines the physical configuration of the devise and the cables that connect them. Topologies that have been employed for LANs (and WANs) are bus, ring, star and tree.
Bit
is a binary digit (0 or 1) with which all computer data is stored
Wireless Application Protocol (WAP)
is a protocol that enables cellphones and other wireless devices to access Web-based info and services.
Database
is an integrated collection of data records and data files. It comprises nothing more than stored data.
Database Management System (DBMS)
is not a database; its a tool. DBMS is a separate computer program that allows an organization to create new databases and use and work with the data in the databases after they have been created. Usually includes a data dictionary or data repository
Network Operating System (NOS)
manages communication over a network. It may be either a peer-to-peer system ( in which all nodes share in communications management) or a client/server system ( in which a central machine serves as the mediator of communication on the network. ex. Server versions of Microsoft Word
Local Area Network (LAN)
permit sharing resources ( software, hardware, and data) amount computers within a limited area. Usually privately owned, which means they don't use telephone lines or that they use private lines leased from telecommunications providers
Communication Devices/ Modems
provides remote access and provides a network with the ability to communicate with others. Ex. modems translate digital data into the analog format needed to use telephone lines. Gateways allow connection of 2 dissimilar networks (a LAN to the Internet)
Operating System
provides the interface between the user and the hardware (software) It defines what commands can be issued and how they are issued (ex. typing in a command) Controls all input and output to main memory, and it may include certain utility programs that might be used stand-alone or in application software
Central Processing Unit (CPU) 2 Principal Components
the control center of the computer system. (hardware) 1. Processor 2. Primary Storage
Transmission Media
the physical path between nodes on a network. It may be wired or wireless.
Voice over Internet Protocol (VoIP)
the routing of voice conversations over the Internet. A protocol called Multiprotocol Label Switching is used on network backbones to label different types of IP traffic for prioritization; voice traffic needs some priority for reasonable conversations.
Internet Based Networks
use Internet protocols and public communications channels to establish network communications. The internet itself is an international network composed of servers around the world that communicate with each other. Internet service providers (ISPs) provide access for individuals to the Internet. Internet Based Networks are used to establish communication among a company's LANs as well as to transmit EDI transactions
Intranets and Extranets
use Internet protocols and public communications media rather than proprietary systems Intranets: connect geographically separate LANs within a company. An intranet is more secure than the Internet because it has restricted users community and local control. Extranets: permit company suppliers, customers, and business partners to have direct access to the company's network.