Chapter 7 Notes

Databases

• Database programs help you to alleviate information overload by: making it possible to store, organize, retrieve, communicate and manage information in ways that wouldn’t be possible without computers

Databases

• Advantages of computerized databases over paper databases They make it easy to store large quantities of informationThey make it easier to retrieve information quickly and flexibly.They make it easy to organize and reorganize information.They make it easy to print and distribute information in a variety of ways.

Databases

The flip side to the conveniences provided by the plethora of databases in use:

Some of the information stored in databases is about you, and you have little or no control over how it is used.

Databases

• Database. - A collection of information stored in an organized form in a computer.

• Table - A collection of related information.

• Record - The information related to one person, product, or event.

• Field - A discrete chunk of information

• field type, or data type - They type of information a field can hold.

• computed field - contains formulas similar to spreadsheet formulas and display values calculated from values in other numeric fields.

Database Queries

• Query - To ask the database for specific information.

• Complex Queries• query language - most programs enable the user to specify the

rules of the search by filling in a dialog box or blank on-screen form, but some require the user to type the request using a special language that is more precise than English is.

• SQL - a standard language supported by most modern database-management programs - stands for Structured Query Language, and pronounced “sequel”

– for programming complex queries.

– Using SQL means that programmers and sophisticated users don’t need to learn new languages when they work with different hardware and software systems.

Printing Reports, Labels and From Letters

mail merge-Many database programs don’t actually print letters, they simply export data, or transmit the necessary records and fields to word processors with mail merge capabilities, which then take on the task of printing the letters.

Directories and Geographic Information Systems

• Electronic phone directory - a database that allows you to link names, address and phone numbers

• Electronic street atlas – can pinpoint an address on a map and print it for you. – Many are designed to work with GPS (global

positioning system) receivers on computers. • GPS satellites feed location information to GPS

receivers• Mapping software uses this information to provide

location feedback

Personal Information Managers

PIM (Personal Information Managers) - the type of specialized database program that is found on a mobile device such as a Palm

Database Management Systems (DBMS)

• The difference between a file manager database and a database-management system (DBMS):

– A file manager is a program that enables users to work with one file at a time

– a DBMS is a system of programs that can manipulate data in a large collection of files - the database - cross-referencing between files as needed.

• Using a DBMS makes things run more efficiently because:

– Information doesn’t have to be repeated in every single table• Key fields unlock the relevant information in the data

table when it's needed elsewhere. • This key field is shared amongst all the tables.

Relational Databases• Relational database - A program that allows tables to be related

to each other so that changes in one table are reflected in other tables automatically.

– DBMS are relational databases

• Interfaces - important to a well-designed database

– They provide different users only with the information and commands they need to get their jobs done

Real-Time Computing• Real-time computing

– Interactive processing - users can interact with data through terminals, viewing and changing values online in real time.

– A multi-user database system run on a powerful database server and accessed by users remotely is needed for applications that demand immediacy.

Downsizing and Decentralizing• client/server approach

– Client programs in computers send information requests through a network or the internet to database servers or mainframe databases.

– These servers process queries and send the requested data back to the client.

It enables users to take advantage of the PC’s simple user interface and convenience, while still having access to data stored on large server systems.

• Methods used by large companies to keep copies of all corporate data

– Data warehouses

– Distributed databases (data spread across networks on several different computers, rather than stored on one central site)

Data Miningdata mining - The discovery and extraction of hidden predictive information from large databases. It uses statistical methods and artificial intelligence technology to locate trends and patterns in data that that would have been overlooked by normal queries.

• Intranet - a business’ internal network that enables employees to access corporate databases using the same Web browsers and search engines they use to access information outside the company networks.

• Building websites

• XML and HTML languages

– HTML - not designed to build database queries.

– XML - more powerful and designed with industrial-strength databases in mind.

– XML can serve as both a query language and a webpage construction tool.

• CRM system - Customer relationship management

– a software system for organizing and tracking information on customers; directories are at the heart of CRM.

Databases and the Web

Databases and the Web dirty data - Data records containing errors.data scrubbing - The process of going through a database and eliminating dirty data with software.

Object-Oriented Databases• Object-oriented databases

– take a different approach to organizing data; • a departure from traditional approaches to programming,

which follow the pattern of inserting data into a set of instructions and then producing output.

• The object-oriented database focuses instead on defining data as objects and then determining how different objects relate and interact with one another.

• To create an Object-oriented database: – define all the objects you plan on storing in the database– define the way each object relates to every other object

within the database– After you identify an object, you put it into a class, or set of

objects. – To define a class you have to determine what data each

object within that class must have and which logic sequences, called methods, will affect those objects.

Object-Oriented Databases– The objects within a system can communicate with you or

other objects using interfaces called messages.

• Advantages to an object-oriented database

– easier to manipulate many forms of data

– they can store and retrieve unstructured data, such as audio and video clips, more efficiently

– programmers developing a new database can save time by reusing objects

No Secrets: Computers and Privacy

The definition of privacy is based on the notion of access, which means physical proximity to a person or knowledge about that person.The US Constitution does not guarantee a right to privacy; it is implied, according to the Supreme Court Identity theft - stealing someone’s personal information for your own illegal use.

The Privacy Problem• Record-matching - combining

database information from databases that share a unique field.

– Beneficial uses: • crime-fighting (NCIC)• establishing credit

records

– Problems:• data errors• data is immortal• data isn’t secure

Code of Fair Information Practices

• No secret government databases

• Individuals can access and correct information about themselves in government databases

• Agencies ensure the reliability and security of database information

– Nearly every European nation passed laws, which shows that it had more impact there than in the US, where business lobbyists blocked issues that they were against.

USA Patriot ActThe FBI can get a search warrant for educational, medical, business, library and religious records by stating they are part of an ongoing investigation. No probable cause needs to be shown.

Threats by Database• Database technology poses more of a threat to privacy because

other information technologies amplify that threat:

– Networks - make it possible for personal data to be transmitted almost anywhere instantly

– Workplace monitoring - enables supervisors to count key strokes, monitor Web activity, remotely view what’s on the screens of employees

– Surveillance - surveillance cameras can be combined with face-recognition software, picture databases, criminal databases; surveillance satellites

– cell phones - required by law to include technology to determine transmit locations to emergency personnel during 911 calls.