c1 sols
Chapter 1 Solutions
Review Questions
1. What is the purpose of an E-R Model? To identify the entities about which the database should store data, and the relationship among those entities.
2. What is an entity? An entity is any person, place, or thing having attributes, or characteristics, of interest to the organization.
3. Give an example of three entities that might exist in a database for a medical office and some of the attributes that would be stored in a table for each entity. Doctor – name, address, Social Security Number, medical ID number; Patient – name, address, Social Security Number, insurance policy information, medical history; Appointment – date, time, patient, doctor.
4. Define a one-to-many relationship. An occurrence of data in one entity results in only one occurrence of data in the other entity.
5. Discuss the problems that can be caused by data redundancy. Can create data anomalies or inconsistencies in the data making it unreliable.
6. Explain the role of a primary key. The primary key is used to uniquely identify each row in a table.
7. Describe how a foreign key is different from a primary key. A foreign key is used to reference or join data in different tables. In most cases, the foreign key references a primary key in another table. In a one-to-many relationship, the foreign key is stored in the “many” entity.
8. List the steps of the normalization process. First, a primary key is identified and any repeating groups are identified. Then any partial dependencies are eliminated. Finally, any transitive dependencies are eliminated.
9. What type of relationship cannot be stored in a database? Why? A many-to-many relationship cannot be stored in a database since there would be no way to restructure or re-join the data correctly.
10. Identify at least three reasons an organization might analyze historical sales data stored in its database. Answers will vary - To determine the necessary inventory levels to support sales
Review Questions
1. What is the purpose of an E-R Model? To identify the entities about which the database should store data, and the relationship among those entities.
2. What is an entity? An entity is any person, place, or thing having attributes, or characteristics, of interest to the organization.
3. Give an example of three entities that might exist in a database for a medical office and some of the attributes that would be stored in a table for each entity. Doctor – name, address, Social Security Number, medical ID number; Patient – name, address, Social Security Number, insurance policy information, medical history; Appointment – date, time, patient, doctor.
4. Define a one-to-many relationship. An occurrence of data in one entity results in only one occurrence of data in the other entity.
5. Discuss the problems that can be caused by data redundancy. Can create data anomalies or inconsistencies in the data making it unreliable.
6. Explain the role of a primary key. The primary key is used to uniquely identify each row in a table.
7. Describe how a foreign key is different from a primary key. A foreign key is used to reference or join data in different tables. In most cases, the foreign key references a primary key in another table. In a one-to-many relationship, the foreign key is stored in the “many” entity.
8. List the steps of the normalization process. First, a primary key is identified and any repeating groups are identified. Then any partial dependencies are eliminated. Finally, any transitive dependencies are eliminated.
9. What type of relationship cannot be stored in a database? Why? A many-to-many relationship cannot be stored in a database since there would be no way to restructure or re-join the data correctly.
10. Identify at least three reasons an organization might analyze historical sales data stored in its database. Answers will vary - To determine the necessary inventory levels to support sales