ITEC36 (Sir Noel) Flashcards by Caila Aclan

known facts that can be recorded and have an implicit meaning

Data

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it is a processed data by a computer to become more useful

Information

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it is a collection of related data

Database

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it is a collection of programs which enables its users to access database, manipulate data, reporting and representaion of data

Database Management System

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it is an organized collection of structured infromation, or data, typically stored electronically in a computer system

Database

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it access different parts of data and formulate the result of a request presentation and visualization of data

Queries

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that may read some data and “update” certain values or generate new data and store that in the database

Transactions

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used to hide storage details and present the users with a conceptual view of the database

Data Model

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refer to the data model constructs rather than data storage details

program

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supports only one user at a time

Single User Database

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supports multiple users at the same time

MultiUser Database

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Database can be classified according to:

Number of Users
Database Location
Expected Type and Extent of Use

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Data distributed across several different site

Distributed Database

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database is located at a single site

Centralized Database

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database is located within more than one site

Decentralized Database

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stores data used for tactical or strategic decision

Data Warehouse

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supports a companies day to day operations

Operational Database

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are the ones who really use and take the benefits of the database

Database User

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Users may be divided into:

Actors on the scene
Workers behind the scene

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Responsible for authorizing access to the database, for coordinating and monitoring its use, acquiring software and hardware resources, controlling its use and monitoring effieciency of operations

Database Administrators

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Responsible to define the content, the structure, the constraints, and functions
ot transactions against the database. They must communicate with the end users and understand their needs.

Database Designers

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access database occasionally when needed

Casual

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they use the data for queries, reports and some of them update the database content.

End Users

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they make up a large section of the end user population

Naive

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These include business analysts, scientists, engineers, others thoroughly familiar with the system capabilities.

Sophisticated

Mostly maintain personal databases using ready-to-use packaged applications

Stand Alone

They understand the user requirements of naïve and sophisticated users and design applications including canned transactions to meet those requirements.

System Analysts

Implement the specifications developed by analysts and test and debug them before deployment.

Application Programmers

There is an increasing need for such people who can analyze vast amounts of business data and real-time data (“Big Data”) for better decision making related to planning, advertising, marketing etc.

Business Analysts

Design and implement DBMS packages in the form of modules and interfaces and test and debug them.

System Designers and Implementors

Design and implement software systems called tools for modeling and designing databases, performance monitoring, prototyping, test data generation, user interface creation, simulation etc. that facilitate building of applications and allow using database effectively.

Tool Developers

They manage the actual running and maintenance of the database system hardware and software environment.

Operators and Maintenance Personnel

5 Advantage of database

Data Independence Data Consistency Controlled Redundancy Data Integrity Data Security

Database structure may evolve as new requirements are defined.

Flexibility to change data structures

Extremely important for on-line transaction systems such as shopping, airline, hotel, car reservations

Availability of current information

Wasteful overlap of resources and personnel can be avoided by consolidating data and applications across departments.

Economies of scale

were introduced in late 1980s and early 1990s to cater to the need of complex data processing in CAD and other applications.

Object-Oriented Database Management Systems (OODBMSs)

was originally introduced in 1970, was heavily researched and experimented within IBM Research and several universities.

Relational model

contains data in HTML (Hypertext markup language) with links among pages

Web

A single unit of logic or work, sometimes made up of multiple operations.

Transaction

is a major part of database applications; allows hundreds of concurrent transactions to execute per second.

OLTP (Online Transaction Processing)

Those who actually use and control the database content, and those who design, develop and maintain database applications

“Actors on the Scene”

Those who design and develop the DBMS software and related tools, and the computer systems operators

“Workers Behind the Scene”

is a vital concept in a database. Only users authorized must be allowed to access the database and their identity must be authenticated using username and password. Unauthorized users shouldn’t be allowed to access the database under any circumstances as its violets the integrity constraints

Data Security

is defined as the storing of the same data in multiple locations.

Data redundancy

is the process of organizing data in a database. This includes creating tables and establishing relationships between those tables according to rules designed both to protect the data and to make the database more flexible by eliminating redundancy and inconsistent dependency.

Normalization

Providing storage structures for efficient query processing

indexes

is the module responsible for executing database queries.

query processor

is the process of selecting an efficient execution plan for evaluating the query.

Query optimization

describe the process of creating and storing copies of data that can be used to protect organizations against data loss.

Backup and recovery

refers to an interactive system that provides access to information and services using different computing platforms.

Multiple-User Interface (MUI)

refers to the correctness and completeness of data within a database.

Data integrity

is defined as a property of DBMS that helps you to change the Database schema at one level of a database system without requiring to change the schema at the next higher level.

Data Independence

in database systems refers to the requirement that any given database transaction must change affected data only in allowed ways.

Data Consistency

occurs in database systems which have a field that is repeated in two or more tables. ... Database normalization prevents redundancy and makes the best possible usage of storage.)

Controlled Redundancy

is the oldest type of the data model. It was developed by IBM in 1968. It organizes data in the tree-like structure

Hierarchical data model

It is the advance version of the hierarchical data model. To organize data it uses directed graphs instead of the treestructure.

Network Data Model

is a database management system that supports the creation and modeling of data as objects.

object-oriented database management system

it is referred to as parent table.

Table

it is referred to as child table.

Related Table

indicates that there can be only one matching record in that table

Number 1

indicates that many records can include the same ID; may appear more than once

The ∞ symbol

When each item in each table only appears at once.

One-To-One (1-1)

When one item in one table can have a relationship to multiple items in another table.

One-To-Many (1-∞)

When one or more items in one table can have a relationship to one or more items in another table.

Many-To-Many (∞-∞)

To prevent invalid data and to keep references in sync across table relationship

Enforce Referential Integrity

To make sure that data in related Fields is updated in all related Tables.

Cascade Update Related Fields

The decision to select this depends on whether you need to retain records in some tables even though they right be deleted from other tables. It is optionally checked in MS Access

Cascade Delete Related Records

supports a small number / a small group of users

Workgroup Database

supports a large number / large number of users (more than one building, multiple buildings, wide area network) 2 or more system

Enterprise Database