Chapter 12 Accessing Databases

Practical PC 5th Edition Chapter 12 Getting Started In this Chapter, you will learn: What’s a database About database software How to create your own database To create databases with spreadsheet software About databases on the Web and on CDs About Hardware: CDs and DVDs Practical PC 5th Edition Chapter 12

Practical PC 5th Edition Chapter 12 What’s a database? A database is a collection of data Structured databases contain information that is organized as fields, records, and files A field contains a single piece of information A record contains fields of information about a single “entity” in the database A group of similarly structured records form a fie A relational database allows you to store information for two or more different types of records and form a link between them Each record type is stored in a table For example, a video store database may include a table of customers and a table of videos When a customer checks out a video a link is made between the two tables Practical PC 5th Edition Chapter 12

Practical PC 5th Edition Chapter 12 What’s a database? Database with linked tables Practical PC 5th Edition Chapter 12

Do I need database software? Database software provides a set of tools to enter and update information in fields Also called a database management system You can enter, delete, sort, and search for records You might access a product database when shopping online or a bank database at an ATM machine Database software offers a wealth of data management capabilities Requires a substantial learning commitment For simple files, you may be able to use the database modules in Microsoft Works You can also use spreadsheet software for simple databases Practical PC 5th Edition Chapter 12

How would I create my own database? Creating a database consists of two tasks: Creating the file structure to hold the data Entering the data A file structure is a specification for the database fields and their characteristics You’ll need to assign a name to each field You may also need to specify the data type and maximum field length You then enter the data carefully and consistently Be consistent with symbols, capitalization, categories, and abbreviations Compare onscreen data against the original documents Practical PC 5th Edition Chapter 12

How would I create my own database? Entering data in Access Practical PC 5th Edition Chapter 12

Can I really create databases with spreadsheet software? You can use spreadsheet software to maintain files of information You cannot use it to join files or tables together to create a relational database You can use the Form View feature in spreadsheet software to view each row as a “card” containing a series of fields You can also filter the data, which is more complicated, but useful for creating reports that show only selected data Practical PC 5th Edition Chapter 12

What about databases on the Web and on CDs? You’ll find many databases on the Web Look up your old roommate in a phone-book-style database Look up flights in a database of flight schedules Check the value of your car in a digital “Blue Book” Web and CD databases can overlap Web is optimal for data that is constantly changing On the Web databases can actively collect information CDs provide a low cost distribution method for less changeable data CDs are more private since your access of the data is not tracked by a cookie or a Web site Practical PC 5th Edition Chapter 12

What about databases on the Web and on CDs? Web and CD databases Practical PC 5th Edition Chapter 12

Practical PC 5th Edition Chapter 12 Hardware: CDs and DVDs CDs Originally invented to hold music CD-ROM Computer CDs are sometimes called CD-ROMs to distinguish them from audio CDs CD-ROM is an abbreviation of “compact disc read-only memory” CD-ROMs are preloaded with data and cannot be used to store additional data Practical PC 5th Edition Chapter 12

Practical PC 5th Edition Chapter 12 Hardware: CDs and DVDs CDs (continued) CD-R and CD-RW CD-R (CD-recordable) data cannot be changed once it is recorded CD-RW (CD-rewritable) allows you to record and then later change the data CD-Rs are considered to be more dependable since some machines have trouble reading CD-RWs created on other machines Most CD drives have R and RW capabilities, and the speeds of the drives vary Practical PC 5th Edition Chapter 12

Practical PC 5th Edition Chapter 12 Hardware: CDs and DVDs CD Drive Speed Varies Practical PC 5th Edition Chapter 12

Practical PC 5th Edition Chapter 12 Hardware: CDs and DVDs DVDs Originally invented to replace VHS tapes Digital Video Disc Storage capacity much greater than a CD-ROM disc Data can be stored in one of four formats depending on number of sides and number of layers used DVDs are available in read-only, recordable, and rewritable formats High Definition DVD is a high-capacity DVD format designed for high definition videos and data storage Practical PC 5th Edition Chapter 12

Hardware: CDs and DVDs DVD storage capacity depends on sides and layers used Practical PC 5th Edition Chapter 12

Practical PC 5th Edition Chapter 12 Hardware: CDs and DVDs Blu-ray disk is a competing format to High Definition DVDs DVD drives often work with more than one type of optical media DVD+R/RW / CD-R/RW combination drive can read and record on both DVDs and CDs Most new PCs include a combination drive Practical PC 5th Edition Chapter 12

Who owns information about me? What do you think? Can you identify an actual incident when you discovered that data about you had been distributed without your approval? Do you accurately fill out questionnaires that you encounter on the Web? Do you think that you have the right to be consulted before anyone distributes information about you? Practical PC 5th Edition Chapter 12

Practical PC 5th Edition Chapter 12 Chapter Summary You should now be able to: Understand what is a database Use database software Create your own database Create databases with spreadsheet software Understand about databases on the Web and on CDs Understand the difference CDs and DVDs Practical PC 5th Edition Chapter 12