Chapter 9 Database Systems

Courtesy of Chris Pascucci, Shelly/Vermaat, Joanne Nichols

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Database Basics Database

– Collection of data on a specific topic or purpose that is stored for future use.

– Data is organized so you can access, retrieve, sort, and edit data.

Database Management System (DBMS)– Software used to create, use, and manage a database.– Create forms, reports, and queries.

Database System– Comprised of a database, DBMS, and applications.– Applications such as e-commerce and scheduling.– University example: registration applications, financial applications,

etc…

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Database Basics Data

– Unprocessed items like raw facts, numbers, text, etc…

Information– Data that has been processed in an organized and meaningful way.

A major function of a computer is to process data into information.

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Database Integrity Data Integrity is maintained when

data is accurate and up-to-date.

Garbage In, Garbage Out (GIGO) – computer phrase that means you

cannot create correct information from incorrect data.

Garbage out

Garbage in

Data integrity is lost

Characteristics of Information

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Accurate Verifiable Timely

Organized Accessible Useful

Cost-effective

Data dictionary A data dictionary contains data about each

file in the database and each field in those files

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Validating Data

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Alphabetic/Numeric check Range check Consistency check

Completeness check Check digit Other checks

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Database Systems Multiple users can interact with the same database

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The Hierarchy of Data A database contains files, files contain records, and records

contain fields. Database

– A collection of integrated and related files.

Files– A collection of related records.

Records– A collection of related fields.

Fields– A collection of characters that describe some aspect of an object.– A single piece of information like a name, number, city, state, etc…

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The Hierarchy of Data

Hierarchy of Data

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Data File Example

key field

records fields

2 East Penn Drive

99 Tenth Street

33 Timmons Place

33099 Clark Street

54 Lucy Court

Address

Pittsboro

Carmel

Cincinnati

Montgomery

Shelbyville

City

INRuizAdelbert3928

INElena4872

OHDrakeLouella3876

ALMurrayShannon2928

INBrewerMilton2295

StateLast NameFirst NameMember ID

Gupta

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Database Management Systems

File Maintenance

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Adding Records

Modifying Records

Deleting Records

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Benefits of Using a DBMS Enter data quickly and easily. Organize records in different and useful ways. Locate records quickly. Eliminate redundant data. Create queries for specific data. Create reports.

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DBMS

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Database Approach to Data Management

Database Approach– Many applications and users can share data in a database.– Secures data so only authorized users can access it.

• Access privileges (none, read-only, full-update)• Principle of least privilege

– Provides means to backup data.– Requires a DBMS.

File Processing System Approach– Each department/area within an organization has its own set of files.– Data redundancy - same data stored in multiple files.– Isolated data - data stored in files at various physical locations -

difficult to access.

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Benefits of Using a Database Approach

File Processing vs DBMS

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Database Management Creating and implementing the right database system

involves:– Determining how data is stored and retrieved.– How people will see and use the database.– How the database will be created and maintained.– How reports and documents will be generated.

Types of Databases Relational Databases (most commonly used) Object-Oriented Databases Multi-Dimensional Databases (used for data warehouses) Others…

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Relational Databases A relational database stores data in a table that consists of

rows and columns.

Most common type of database used for payroll, inventory, ordering, and other business-related functions.

Also stores data relationships, which are connections within data.

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Relational Databases

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Object-Oriented Databases An object-oriented database stores data in objects.

An object is an item that contains data, as well as actions that read and process the data.

Mainly used for multimedia databases (video, audio, graphics), CAD (computer aided design) , and Web databases.

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Multi-Dimensional Databases A multi-dimensional database stores data in dimensions.

Multiple dimensions, also called hypercube, allow users to analyze any view of data.

Can consolidate data much faster than relational database.

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Multi-Dimensional Databases

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Large-Scale Databases Data-Warehouse

– Huge database that stores and manages massive amounts of data.– Holds important information from a variety of sources.– Usually a subset of multiple database.

Data Mart– Smaller version of a data warehouse.– Often developed for a specific purpose.

• Examples: sales department, inventory and shipping department, finance department, upper level management, and so on. Regional operating centers might each have their own data mart that contributes to the master data warehouse

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Large-Scale Databases Data-Mining

– A technique used to extract information from a data warehouse or a data mart.

– Sort through huge amounts of data to find patterns and establish relationships among the data.

Business Intelligence– Business use of data mining can help increase efficiency, reduce

costs, or increase profits.– Identifies trends.– Identifies patterns in customer behaviors.

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Example of Data Mining Wal-Mart captures point-of-sale transactions from over 2,900

stores in 6 countries and continuously transmits this data to its massive 500+ terabyte data warehouse. 1 Terabyte = 1 trillion characters (bytes)

Can determine what products are selling well or poorly in which regions.

Database is refreshed every hour.

Wal-Mart allows more than 3,500 suppliers to access data on their products and perform data analyses.

These suppliers use this data to identify customer buying patterns at the store display level. They use this information to manage local store inventory and identify new merchandising opportunities.

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Data Mining Some concerns regarding Data-Mining

– DARPA (Defense Advanced Research Projects Agency ) developed project TIA (Terrorism Information Awareness).

• Main goal of TIA is to preemptively uncover and disrupt terrorist attacks.• TIA helps U.S. government monitor daily transactions such as, credit card

transactions, airline tickets, rental car, passport, driver’s license, etc…– Medical Information

• Prescription reminders sent from a pharmacy require access to certain personal information.

• Profiling patients based on factors such as, age, gender, disease, etc…– Clinicians must make patients aware of how their information may be used.

– Limitations:• Data mining tools are not self-sufficient applications and require trained specialists

to analyze the information generated by these tools.• Patterns and connections that are found depend on “Real World” circumstances

that may be casual and not necessarily be a threat.

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Databases How are databases important to us?

Shop for products or

services

Buy or sell stocks

Search for a job

Make airline reservations

Register for college classes

Check semester grades

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Databases in Action

NCIC – National Crime Information Center FBI’s huge database created in 1967 under J. Edgar Hoover. Over 15 million active records in 19 files. Makes available a variety of records for law enforcement and security

purposes. Information in this database assists in:

– Apprehending fugitives– Locating missing persons– Locating and returning stolen property

http://www.fbi.gov/about-us/cjis/ncic

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Databases in Action

National DNA Database Originally intended for sex offenders – has since been extended to

include almost any criminal offender. FBI uses this database to store missing persons DNA. Stores DNA crime scenes samples. Used to ID unidentified human remains. US has over 9 million records in CODIS

(Combined DNA index system) – largest

DNA DB in the world!

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Databases in Action

National Security Agency (NSA) Database “largest database ever assembled in the world”, from unnamed source in

the NSA. Contains hundreds of billions of records of telephone calls. Existence of this database and the NSA program that compiled it was

unknown to the general public until USA TODAY broke the story in May 2006.

Records and saves all phone calls ever made and all telecommunications via a “black room” called “Room 641A”.

Supercomputers analyze all data in their database

to find certain flags.– Terrorist chatter