MIT Chapter 7

data management (tools)

- simple data management software packages - easy to use and update such as personal information manages (PIMs)

database models

-hierarchical, network, relational, object-oriented, object-relational

centralized database approach to data mangement

-multiple application programs share a pool of related data - stored in a central location (data center), such as grocery store chain - more efficient and less prone to errors -requires a DBMS -reduces Data Redundancy - when data is copied, stored, and used from different locations - difficult to manage due to constant changes

good data

-nonredundant, flexible, simple and adaptable to a number of different applications

relational model

-to describe data using a standard tabular format -all data elements are placed in two-dementional tables called Relations, that are to logical equivalent files -tables in relational models organize data in rows and columns, simplifying data access and modification

one-to-many relationship

1 and infinity symbols on the relationship lines -1 - one record for each table entry -infinity - each of the 1 can have a number of the next table -one to one or many to many relationships

key

a field in a record that is used to identify the record (EmployeeNumber)

relationship

ability to connect data in different tables through common field

database types - multiuser - database development platform

allow multiple employees to access and edit simultaneously - businesses - allow you to create a database and DBMS for accessing and manipulating data in database

business intelligence

business use of data mining to increase efficiency, reduce costs, increase profits

field types - computed field

calculated field - calculated from other fields instead of being entered into the database

field types - alphanumeric

character data includes characters or numbers that cannot be manipulated or used in calculations

attribute

characteristic of an entity (employee number, name, hire date) -selected to capture relevant characteristics of entities

data center

climate-controlled building or set of buildings that house the servers that store and deliver mission-critical information and services (corporate databases and DBMS)

database

collection of data (integrated and related files or tables) organized to meet users' needs

data definition language (DDL)

collection of instructions and commands used to define and describe data and data relationships in a specific database (schemas entered into a DBMS using DDL)

record

collection of related field that describe some object or activity - can create a more complete description (name, time, artist, price, release date, track #)

file (table)

collection of related records (itunes music library)

unstructured databases

contains data that is difficult of impossible to place in a traditional database system - notes, drawings, fingerprints, medical abstracts, sound recordings

field types - logical field

contains items such as yes or no

field types - numeric field

contains numbers that can be used in making calculations

database backup

copy of all or part of database on second storage device

databases can be..

critical or corresponding responses across diverse functional areas of an organization -controversial - privacy and even civil rights are being violate? - databases of people's information

data integrity

data stored in database is accurate and up to date

characteristics of databases - amount

database size - depends on number of records or files - determines overall storage resuirement

replicated database

database that holds duplicate set of frequently used data - send at beginning and end of the dat

database system or database environment

database, DBMS, and application programs that utilize the data

lights out environment

databases being automated and can run/manage themselves while being monitored remotely

database types - single user

databases for personal computers - only one person can use at a time -microsoft outlook, quicken - store and manipulate personal data

back-end application

dbms that interacts with other programs and databases; indirectly interacts with users

front-end application

dbms that is one that directly interacts with users

schema

description of outline the logical and physical structure of data and relationships among the data in a database

database types - special-purpose database

designed for one purpose or limited number of applications

data dictionary

detailed description of all data used in the database - standards definitions of terms and data elemnts that can be referenced by programmers, data administrators, and users to maintain data integrity

end-user computing

development and use of application programs and computer systems by users who are not computer system professionals

database design - input and output interface design

effective interfaces - convenient and powerful database design feature

garbage in, garbage out (GIGO)

entering inaccurate data into a database that results in inaccuracies; too old and no longer valid

field name

every field has one and can have either fixed or variable length - no spaces in database syntax (EmployeeNumber)

comma-separated values (CSV)

flat file format - uses line breaks and commas to interpret data as a table -simple, standardized and understood by many different databases

entity

generalized class of people, places, or things (objects) for which data is collected, stored, and maintained (CDs, employees, inventory) -data about entities are stored and represented as records in a database

entity relationship diagram

illustration of relationships between tables

data manipulation: selecting

involves choosing data based on certain criteria

data manipulation: joining

involves combining two or more tables -key to flexibility and power of relational databases

continuity planning

involves disaster recovery - important to government agencies that maintain information on which national security depends

data warehouse

large database that holds important information form a variety of sources

characteristics of databases - volatility

measure of changes - additions, deletions, modifications - typically require in a given time period

characteristics of databases - immediacy

measure of how rapidly changes must be made to data

database design - record and table design

must identify exact fields that are contained in each record and types of records that may be included in each table

master files

permanent files that are updated over time

anomalies

problems and irregularities in data such as two s. thomas without a unique identification code -- add a primary key

normalization

process of correcting data problems or anamolies - to ensure the database contains "good data"

data mining

process of extracting information from data warehouse or data mart

database recovery

process of returning database to original, correct condition if database has crashed or been corrupted

data analysis

process that involves evaluating data to identify problems with content of database

disaster recovery

providing a plan for hwo to bring systems back online after an emergency

characters

represented by bytes (basic building block of information). can be upper/lowercase, numbers, special symbols

database systems in organizations

routine processing, information and decision support, data warehouse and data marts and data mining

query by example (QBE)

siual appraoch to making queries or getting ansers to wuestions by entering names, values, and other items into a window -easier and faster than learning formal DMLs and SQL

database administrators (DBAs)

skilled and trained computer professionals who direct all activities related to an organization's database, including providing security from intruders

data mart

small data warehouse, often developed for specific person or purpose - generated from data warehouse using DBMS

field

smallest practical unit in most databases -typically a name, numer, or combination of characters that in some way describes an aspect of an object or activity.

Database Management System (DBMS)

software that accesses databases - group of programs that manipulate the database and provide an interface between the database and the user/application programs -store important data for various people groups -perform routine tasks -providing information to help make better decisions -ensure data is protected and safe from attackers

data item

specific attribute - can be found in fields of the record describing the entity (DNA test results)

data manipulation language (DML)

specific language provided with DBMS that allows people and other databse users to access, modify, and make queries about data contained in databse and to generate reports

database design - field design

specify type, size, format and other aspects of each field

standardized query language (SQL)

standardized query manipulation language for relational databases

database types - flat file

stores databse records in plain text file -stores each record as a line of text that is separated by commas etc

transaction files

temporary files that contain data representing transactions or actions that must be taken (number of hours employee worked last week, sales order from yesterday) -cause changes to master files

data hierarchy

the manner in which data in a database is organized into sequential levels of detail -characters are combined to make fields -fields are combined to make a record -records are combined to make a file -files are combined to make a database

storage area network (SAN)

to connect multiple storage devices on high-speed network to make recovering from failure faster and more efficient

redundant array of independent disks (RAID)

to store data on multiple disks

primary key

uniquely identifies a record - no other record can have the same primary key -essential for DBMS functioning -unique id number for multiple fields as a primary key

database types - open-source database

used by travel agencies, manufacturing companies, etc -strong community support, customizable, free

database types - general-purpose database

used for a large number of applications -oracle, sybase, IBM

distributed databases

virtualized database - actual data may be spread across several databases at different locations - appear to be single, unified database, but connections data at different locations via telecommunications -controlling accesses and changes data sometimes difficult