Database Systems: Design, Implementation and Management 13th Edition solution manual
Chapter 1
Database Systems
Discussion Focus
How often have your students heard that “you have only one chance to make a good first impression?” That’s why it’s so important to sell the importance of databases and the desirability of good database design during the first class session.
Start by showing your students that they interact with databases on a daily basis. For example, how many of them have bought anything using a credit card during the past day, week, month, or year? None of those transactions would be possible without a database. How many have shipped a document or a package via an overnight service or via certified or registered mail? How many have checked course catalogs and class schedules online? And surely all of your students registered for your class? Did anybody use a web search engine to look for – and find – information about almost anything? This point is easy to make: Databases are important because we depend on their existence to perform countless transactions and to provide information.
If you are teaching in a classroom equipped with computers, give some “live” performances. For example, you can use the web to look up a few insurance quotes or compare car prices and models. Incidentally, this is a good place to make the very important distinction between data and information. In short, spend some time discussing the points made in Section 1.1, "Why Databases?" and Section 1.2 “Data vs. Information.”
After demonstrating that modern daily life is almost inconceivable without the ever-present databases, discuss how important it is that the (database) transactions are made successfully, accurately, and quickly. That part of the discussion points to the importance of database design, which is at the heart of this book. If you want to have the keys to the information kingdom, you’ll want to know about database design and implementation. And, of course, databases don’t manage themselves … and that point leads to the importance of the database administration (DBA) function. There is a world of exciting database employment opportunities out there.
After discussing why databases, database design, and database administration are important, you can move through the remainder of the chapter to develop the necessary vocabulary and concepts. The review questions help you do that … and the problems provide the chance to test the newfound knowledge.
Answers to Review Questions
1. Define each of the following terms:
a. data
Raw facts from which the required information is derived. Data have little meaning unless they are grouped in a logical manner.
b. field
A character or a group of characters (numeric or alphanumeric) that describes a specific characteristic. A field may define a telephone number, a date, or other specific characteristics that the end user wants to keep track of.
c. record
A logically connected set of one or more fields that describes a person, place, event, or thing. For example, a CUSTOMER record may be composed of the fields CUST_NUMBER, CUST_LNAME, CUST_FNAME, CUST_INITIAL, CUST_ADDRESS, CUST_CITY, CUST_STATE, CUST_ZIPCODE, CUST_AREACODE, and CUST_PHONE.
d. file
Historically, a collection of file folders, properly tagged and kept in a filing cabinet. Although such manual files still exist, we more commonly think of a (computer) file as a collection of related records that contain information of interest to the end user. For example, a sales organization is likely to keep a file containing customer data. Keep in mind that the phrase related records reflects a relationship based on function. For example, customer data are kept in a file named CUSTOMER. The records in this customer file are related by the fact that they all pertain to customers. Similarly, a file named PRODUCT would contain records that describe products – the records in this file are all related by the fact that they all pertain to products. You would not expect to find customer data in a product file, or vice versa.
2. What is data redundancy, and which characteristics of the file system can lead to it?
Database Systems
Discussion Focus
How often have your students heard that “you have only one chance to make a good first impression?” That’s why it’s so important to sell the importance of databases and the desirability of good database design during the first class session.
Start by showing your students that they interact with databases on a daily basis. For example, how many of them have bought anything using a credit card during the past day, week, month, or year? None of those transactions would be possible without a database. How many have shipped a document or a package via an overnight service or via certified or registered mail? How many have checked course catalogs and class schedules online? And surely all of your students registered for your class? Did anybody use a web search engine to look for – and find – information about almost anything? This point is easy to make: Databases are important because we depend on their existence to perform countless transactions and to provide information.
If you are teaching in a classroom equipped with computers, give some “live” performances. For example, you can use the web to look up a few insurance quotes or compare car prices and models. Incidentally, this is a good place to make the very important distinction between data and information. In short, spend some time discussing the points made in Section 1.1, "Why Databases?" and Section 1.2 “Data vs. Information.”
After demonstrating that modern daily life is almost inconceivable without the ever-present databases, discuss how important it is that the (database) transactions are made successfully, accurately, and quickly. That part of the discussion points to the importance of database design, which is at the heart of this book. If you want to have the keys to the information kingdom, you’ll want to know about database design and implementation. And, of course, databases don’t manage themselves … and that point leads to the importance of the database administration (DBA) function. There is a world of exciting database employment opportunities out there.
After discussing why databases, database design, and database administration are important, you can move through the remainder of the chapter to develop the necessary vocabulary and concepts. The review questions help you do that … and the problems provide the chance to test the newfound knowledge.
Answers to Review Questions
1. Define each of the following terms:
a. data
Raw facts from which the required information is derived. Data have little meaning unless they are grouped in a logical manner.
b. field
A character or a group of characters (numeric or alphanumeric) that describes a specific characteristic. A field may define a telephone number, a date, or other specific characteristics that the end user wants to keep track of.
c. record
A logically connected set of one or more fields that describes a person, place, event, or thing. For example, a CUSTOMER record may be composed of the fields CUST_NUMBER, CUST_LNAME, CUST_FNAME, CUST_INITIAL, CUST_ADDRESS, CUST_CITY, CUST_STATE, CUST_ZIPCODE, CUST_AREACODE, and CUST_PHONE.
d. file
Historically, a collection of file folders, properly tagged and kept in a filing cabinet. Although such manual files still exist, we more commonly think of a (computer) file as a collection of related records that contain information of interest to the end user. For example, a sales organization is likely to keep a file containing customer data. Keep in mind that the phrase related records reflects a relationship based on function. For example, customer data are kept in a file named CUSTOMER. The records in this customer file are related by the fact that they all pertain to customers. Similarly, a file named PRODUCT would contain records that describe products – the records in this file are all related by the fact that they all pertain to products. You would not expect to find customer data in a product file, or vice versa.
| NOTE Note: Field, record, and file are computer terms, created to help describe how data are stored in secondary memory. Emphasize that computer file data storage does not match the human perception of such data storage. |
2. What is data redundancy, and which characteristics of the file system can lead to it?