9 781292 039756

ISBN 978-1-29203-975-6

Experiencing MISDavid M. Kroenke

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Pearson Education LimitedEdinburgh GateHarlowEssex CM20 2JEEngland and Associated Companies throughout the world

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1. To what extent do you agree with the opinions presented here? To what extent are the concerns expressed here justified? To what extent might they be due to other factors?

2. What problems do you see with the way that the car salesperson stores address data? What will he have to do if he ever does want to send a letter or an email to all of his customers?

3. From his comments, how many different themes are there in his data? What does this imply about his ability to keep his data in a spreadsheet?

4. Does the concern about not sharing data relate to whether or not he uses a database?

5. Apparently, management at the car dealership allows the salespeople to keep their contact data in whatever format they want. If you were management, how would you justify this policy? What disadvantages are there to this policy?

6. Suppose you manage the sales representatives, and you decide to require all of them to use a database to keep track of customers and customer car interest data. How would you sell your decision to this salesperson?

7. Given the limited information in this scenario, do you think a database or a spreadsheet is a better solution?

Discussion Questions

Source: Beyond Fotomedia GmbH/ Alamy

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AccessBigtableByteCassandraColumnsDatabaseDatabase administrationDatabase applicationDatabase application system Database management system (DBMS)DB2DurabilityDynamo

ElasticEnterprise DBMSFieldsFileForeign keysFormKeyLost-update problemMetadataMulti-user processingMySQLNoSQL DBMSOracle Database

Personal DBMSPrimary KeyQueryRecordsRelationRelational databaseReportRowsSQL ServerStructured Query Language (SQL)Table

key termS and conceptS

Q4 hoW do databaSe applicationS make databaSeS more uSeful?

Name and describe the components of a database applica-tion. Explain the need for application programs. For multi-user processing, describe one way in which one user’s work can interfere with another’s. Explain why multi-user database pro-cessing involves more than just connecting another computer to the network. Define two broad categories of DBMS and ex-plain their differences.

Q5 What iS a noSQl dbmS?

Define NoSQL data store and give three examples. Explain how NoSQL will likely be used in organizations and state why learning Microsoft Access is still important to you. Explain what is unusual about the development of these systems. Describe possible consequences of NoSQL on the DBMS product market.

How does the knowledge in this text help you?After learning the concepts presented in this text and with some rudimentary knowledge of Access, you’ll be able to query and extract data to help you know how to solve the problems your organization faces . . . or at least you will be able to pinpoint what the problem is.

Use this Active Review to verify that you understand the ideas and concepts that answer the text study questions.

Q1 What iS the purpoSe of a databaSe?

State the purpose of a database. Explain the circumstances in which a database is preferred to a spreadsheet. Describe the key difference between Figures 1 and 2.

Q2 What iS a databaSe?

Define the term database. Explain the hierarchy of data and name three elements of a database. Define metadata. Using the example of Student and Office_Visit tables, show how re-lationships among rows are represented in a database. Define the terms primary key, foreign key, and relational database.

Q3 What iS a databaSe management SyStem (dbmS)?

Explain why a database, by itself, is not very useful to business users. Name the components of a database application system and sketch their relationship. Explain the acronym DBMS and name its functions. List five popular DBMS products. Explain the difference between a DBMS and a database. Summarize the functions of a DBMS. Define SQL. Describe the major func-tions of database administration.

active revieW

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Database Processing

uSing your knoWledge

1. Suppose you are a marketing assistant for a consumer electronics company and are in charge of setting up your company’s booth at trade shows. Weeks before the shows, you meet with the marketing managers and deter-mine what displays and equipment they want to display. Then, you identify each of the components that need to be shipped and schedule a shipper to deliver them to the trade show site. You then supervise convention personnel as they set up the booths and equipment. Once the show is over, you supervise the packing of the booth and all equipment as well as schedule its shipment back to your home office. When the equipment arrives, you check it into your warehouse to ensure that all pieces of the booth and all equipment are returned. If there are problems due to shipping damage or loss, you handle those problems. Your job is important; at a typical show, you are respon-sible for more than a quarter of a million dollars’ worth of equipment.a. You will need to track data about booth components,

equipment, shippers, and shipments. List typical fields for each type of data.

b. Could you use a spreadsheet to keep track of this data? What would be the advantages and disadvantages of doing so?

c. Using your answer to part a, give an example of two re-lationships that you need to track. Show the keys and foreign keys for each.

d. Which of the following components of a database ap-plication are you likely to need: data entry forms, re-ports, queries, or application program? Explain one use for each that you will need.

e. Will your application be for one user or for multiple us-ers? Will you need a personal DBMS or an enterprise DBMS? If a personal DBMS, which product will you use?

2. Samantha Green owns and operates Twigs Tree Trim-ming Service. Recall that Samantha has a degree from a forestry program and recently opened her business in St. Louis, Missouri. Her business consists of many one-time operations (e.g., remove a tree or stump), as well as recur-ring services (e.g., trimming customers’ trees every year or two). When business is slow, Samantha calls former cli-ents to remind them of her services and of the need to trim their trees on a regular basis.a. Name and describe tables of data that Samantha will

need to run her business. Indicate possible fields for each table.

b. Could Samantha use a spreadsheet to keep track of this data? What would be the advantages and disadvan-tages of doing so?

c. Using your answer to question a, give an example of two relationships that Samantha needs to track. Show the keys and foreign keys for each.

d. Which of the following components of a database ap-plication is Samantha likely to need: data entry forms, reports, queries, or application program? Explain one use for each that she needs.

e. Will this application be for one user or for multiple us-ers? Will she need a personal DBMS or an enterprise DBMS? If a personal DBMS, which product will she use?

3. YourFire, Inc., is a small business owned by Curt and Julie Robards. Based in Brisbane, Australia, YourFire man-ufactures and sells YourFire, a lightweight camping stove. Recall that Curt used his previous experience as an aero-space engineer to invent a burning nozzle that enables the stove to stay lit in very high winds. Using her industrial design training, Julie designed the stove so that it is small, lightweight, easy to set up, and very stable. Curt and Julie sell the stove directly to their customers over the Internet and via phone. The warranty on the stove covers 5 years of cost-free repair for stoves used for recreational purposes.

YourFire wants to track every stove and the customer who purchased it. They want to know which customers own which stoves in case they need to notify customers of safety problems or need to order a stove recall. Curt and Julie also want to keep track of any repairs they have performed.a. Name and describe tables of data that YourFire will

need. Indicate possible fields for each table.b. Could YourFire use a spreadsheet to keep track of this

data? What would be the advantages and disadvan-tages of doing so?

c. Using your answer to question a, give an example of two relationships that YourFire needs to track. Show the keys and foreign keys for each.

d. Which of the following components of a database ap-plication is YourFire likely to need: data entry forms, re-ports, queries, or application program? Explain one use for each needed component.

e. Will this application be for one user or for multiple us-ers? Will YourFire need a personal DBMS or an enter-prise DBMS? If a personal DBMS, which product will it use? If an enterprise DBMS, which product can it ob-tain license-free?

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Database Processing

collaboration exerciSe 5

Consider using Google Drive, Google+, Windows Live SkyDrive, Microsoft SharePoint, or some other collaboration tool.

Figure 16 shows a spreadsheet that is used to track the as-signment of sheet music to a choir—it could be a church choir or school or community choir. The type of choir does not mat-ter, because the problem is universal. Sheet music is expensive, choir members need to be able to take sheet music away for practice at home, and not all of the music gets back to the in-ventory. (Sheet music can be purchased or rented, but either way, lost music is an expense.)

Look closely at this data and you will see some data integ-rity problems—or at least some possible data integrity prob-lems. For one, do Sandra Corning and Linda Duong really have the same copy of music checked out? Second, did Mozart and J. S. Bach both write a Requiem, or in row 15 should J. S. Bach actually be Mozart? Also, there is a problem with Eleanor Dixon’s phone number; several phone numbers are the same as well, which seems suspicious.

Additionally, this spreadsheet is confusing and hard to use. The column labeled First Name includes both people names and the names of choruses. Email has both email addresses and composer names, and Phone has both phone numbers and copy identifiers. Furthermore, to record a checkout of music the user must first add a new row and then reenter the name of the work, the composer’s name, and the copy to be checked out. Finally, consider what happens when the user wants to find all copies of a particular work: The user

will have to examine the rows in each of four spreadsheets for the four voice parts. In fact, a spreadsheet is ill suited for this application. A database would be a far better tool, and situa-tions like this are obvious candidates for innovation.

1. Analyze the spreadsheet shown in Figure 16 and list all of the problems that occur when trying to track the assign-ment of sheet music using this spreadsheet.

2. The following two tables could be used to store the data in Figure 16 in a database:ChoirMember (LastName, FirstName, Email, Phone, Part)

MusicalWork (NameOfWork, Composer, Part, CopyNumber) Note: This notation means there are two tables, one

named ChoirMember and a second named MusicalWork. The ChoirMember table has five columns: LastName, FirstName, Email, Phone, and Part; MusicalWork has four columns: NameOfWork, Composer, Part, CopyNumber.a. Redraw the data in Figure 16 into this two-table format.b. Select primary keys for the ChoirMember and Musical-

Work tables.c. The two tables are not integrated; they do not show

who has checked out which music. Add foreign key col-umns to one of the tables to integrate the data.

d. This two-table design does not eliminate the potential for data integrity problems that occur in the spread-sheet. Explain why not.

figure 16Spreadsheet Used for Assignment of Sheet Music

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Database Processing

3. A three-table database design for the data in the spread-sheet in Figure 16 is as follows:

ChoirMember (LastName, FirstName, Email, Phone, Part)MusicalWork (NameOfWork)CheckOut (LastName, FirstName, NameOfWork, Part, CopyNumber, DateOut, DateIn)a. Redraw the data in Figure 16 into this three-table

format.b. Identify which columns are primary keys for each of

these tables.c. The foreign keys are already in place; identify which

columns are foreign keys and which relationships they represent.

d. Does this design eliminate the potential for data integ-rity problems that occur in the spreadsheet? Why or why not?

4. Assume you manage the choir and you foresee two possibilities:• Keepthespreadsheet,butcreateprocedurestoreduce

the likelihood of data integrity problems.• CreateanAccessdatabaseanddatabaseapplication

for the three-table design.Describe the advantages and disadvantages of each of these possibilities. Recommend one of these two possibilities and justify your recommendation.

caSe Study 5

Fail Away with Dynamo, Bigtable, and Cassandra

As you learned in Case Study 1, Amazon.com processed more than 158 order items per second on its peak day of the 2010 holiday sales season. To do that, it processed customer transac-tions on tens of thousands of servers. With that many comput-ers, failure is inevitable. Even if the probability of any one server failing is .0001, the likelihood that not one out of 10,000 of them fails is .9999 raised to the 10,000 power, which is about .37. Thus, for these assumptions the likelihood of at least one failure is 63 percent. For reasons that go beyond the scope of this dis-cussion, the likelihood of failure is actually much greater.

Amazon.com must be able to thrive, even in the presence of such constant failure. Or, as Amazon.com engineers stated: “Customers should be able to view and add items to their shopping cart even if disks are failing, network routes are flap-ping, or data centers are being destroyed by tornados.”6

The only way to deal with such failure is to replicate the data on multiple servers. When a customer stores a Wish List, for example, that Wish List needs to be stored on different, separated servers. Then, when (notice when, not if ) a server with one copy of the Wish List fails, Amazon.com applications obtain it from another server.

Such data replication solves one problem but introduces another. Suppose that the customer’s Wish List is stored on

servers A, B, and C and server A fails. While server A is down, server B or C can provide a copy of the Wish List, but if the cus-tomer changes it, that Wish List can only be rewritten to serv-ers B and C. It cannot be written to A, because A is not running. When server A comes back into service, it will have the old copy of the Wish List. The next day, when the customer reopens his or her Wish List, two different versions exist: the most recent one on servers B and C and an older one on server A. The customer wants the most current one. How can Amazon.com ensure that it will be delivered? Keep in mind that 9 million orders are being shipped while this goes on.

None of the current relational DBMS products was designed for problems like this. Consequently, Amazon.com engineers developed Dynamo, a specialized data store for reliably processing massive amounts of data on tens of thou-sands of servers. Dynamo provides an always-open experience for Amazon.com’s retail customers; Amazon.com also sells Dynamo store services to others via its S3 Web Services prod-uct offering.

Meanwhile, Google was encountering similar problems that could not be met by commercially available relational DBMS products. In response, Google created Bigtable, a data store for processing petabytes of data on hundreds of thou-sands of servers.7 Bigtable supports a richer data model than Dynamo, which means that it can store a greater variety of data structures.

6Giuseppe DeCandia, Deniz Hastorun, Madan Jampani, Gunavardhan Kakulapati, Avinash Lakshman, Alex Pilchin, Swami Sivasubramanian, Peter Vosshall, and Werner Vogels, “Dynamo: Amazon’s Highly Available Key-Value Store,” Proceedings of the 21st ACM Symposium on Operating Systems Principles, Stevenson, WA, October 2007.7Fay Chang, Jeffrey Dean, Sanjay Ghemawat, Wilson C. Hsieh, Deborah A. Wallach, Mike Burrows, Tushar Chandra, Andrew Fikes, and Robert E. Gruber, “Bigtable: A Distributed Storage System for Structured Data,” OSDI 2006: Seventh Symposium on Operating System Design and Implementation, Seattle, WA, November 2006. Available at http://labs.google.com/papers/bigtable.html (accessed June 2011).

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