XP Practical PC, 3e Chapter 12 1 Accessing Databases.

Practical PC, 3eChapter 12

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XP

Chapter 12

Accessing Databases


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XPAccessing Databases

• In this Chapter, you will learn:– What a database is

– About database software

– How to create databases

– How to use spreadsheet software to create a database

– How to use databases on the Web and CDs

– How to make your own CD

– About CDs and DVDs


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XPWhat is a database?

• A database is a set of data, such as your phone book or list of CDs that you own.

• When the database is only loosely structured or grouped, it is called a freeform database.

• When the database is organized into a group of data fields, records or files, it is called a structured database.


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• The information in a structured database is organized as:– Fields – single piece of information such as name or

phone number

– Records – all of the information in the database about a single entity such as a person

– File – a group of related records such as a phone book

• When two or more related files are treated as one unit, it is called a relational database.


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A relational database

Files can be linked by a field to show related information

A file or series of records

A record for the Star Wars movie

A field is the smallest unit of data such as the checkout date


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XPDo I need database software?

• Database management software (DBMS) is specialized software with tools to manage databases.

• It will make it easy for you to create records, edit fields, sort and search files and create reports.

• Frequently the databases you use are maintained by other sites and they provide the software.

• You only need special software if you intend to create and maintain your own databases.


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XPDo I need database software?

An access database

The tables hold the data records

Forms define a way of displaying the data

Reports help organize and display the records

Queries helps search the file


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XPCreating your own database

• To create a database, you must set up the structure and then add in the data records.

• The file structure tells the software what fields you want and their characteristics.

• You might specify file name, size and type of data – such as text, numbers or date, for instance.

• The database software will set up an entry form for you to put data into.


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• Tips to remember when entering data:– Verify data accuracy as you enter

– Be consistent with fields used to group data

– Be consistent with capitalization

– Use correct spelling

– Be consistent when using abbreviations

– Be careful about the use of symbols and formatting of fields such as telephone numbers


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Using Access to create a database


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XPUsing spreadsheet software to create a database

• Spreadsheet software can be used to create simple databases, but not to join files together into relational databases.

• You can also sort, search and create reports.• Spreadsheet software also has a Form view that

will give you a data entry form.• You can also filter or extract data to produce

reports using only selected data.


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XPUsing spreadsheet software to create a database

Excel’s Form view for entering data

Buttons allow easy adding, deleting and finding

Each row contains data for one record

The data from each record is displayed as a “card”


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XPDatabases on the Web and CDs

• The Web and CDs contain much information in databases that can be researched and used.

• You can find a copy of a used book, look for the best airfares, read old copies of newspapers, etc.

• Web databases are good to handle data that is constantly changing.

• CDs are good for more private data or for data that is relatively stable.


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XPHardware – CDs and DVDs

• CDs have become a common media for:– Music and other audio data

– Computer data storage (650 MB) – these are sometimes called CD-ROMs where ROM is read only memory.

– CD-R CD recordable technology allows you to write once on a compact disk

– CD-RW rewritable technology allows changing data already written on the CD


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A comparison of drive speeds for

CD-ROMs


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• DVDs (Digital Video Discs):– Designed to replace video tapes

– Can store entire movies

– Hold up to 9 hours of video or 30 hours of audio files.

– Holds from 4.7 to 10.0 GB of data

– Access rates of between 600KB to 3.32 MB per second

• The most modern, DVD-2 drives, read DVDs, CD-R, and CD-RW disks.

• CDs and DVDs are optical storage technology


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• Optical storage technology:– Records data as tiny pits in the disk surface.

– Data is read with a beam of laser light.

– Is very durable and only susceptible to scratching or very high temperatures.

– Is the best choice for storing and distributing large, fairly stable files.


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The pits on optical storage media

A magnification of the size and spacing of pits on a CD-ROM

A magnification of the size and spacing of pits on a DVD-ROM


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XPWhat do you think?

Who owns information about me?

1. Can you identify an actual incident when you discovered the data about you had been distributed without your approval?

2. Do you accurately fill out all questionnaires that you encounter on the web?

3. Do you think that you have a right to be consulted before anyone distributes information about you?


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XPChapter Summary

• You should now be able to:– Understand the concepts and parts of a database

– Understand the uses of database software

– Create a database

– Use spreadsheet software to create a database

– Use databases on the Web and on CDs

– How to create a CD

– Understand the basic types and uses of CDs, DVDs and the hardware that read/writes them

Date post:	23-Dec-2015
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XP Practical PC, 3e Chapter 12 1 Accessing Databases.

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