What is the relationship between • An entity and a record?
• An attribute and a field?
• An entity set and a file?
2. What is sequential access? What is direct access? Which of the two is more important in today’s business environment? Why?
3. What are the two kinds of data redundancy, and what are the three types of problems that they cause in the information system environment?
4. What expectation should there be for a database management system with regard to handling multiple relationships? Why?
5. What expectation should there be for a database management system with regard to handling data control issues such as data security, backup and recovery, and concurrency control? Why?
6. What expectation should there be for a database management system with regard to in- dependence? Why?
7. Consider a hospital in which each doctor is responsible for many patients while each patient is cared for by just one doctor. Each doctor has a unique employee number, name, telephone number, and office number. Each patient has a unique patient number, name, home address, and home telephone number.
a. What kind of relationship is there between doctors and patients?
b. Develop sample doctor and patient data and construct two files in the style of Figure 3.5 in which to store your sample data.
c. Do any fields have to be added to one or the other of the two files to record the relationship between doctors and patients? Explain.
d. Merge these two files into one, in the style of Figure 3.6. Does this create any problems with the data? Explain.