database mgnt
Given the file structure shown in Figure P1.1, answer Problems 1 - 4.
FIGURE P1.1 The File Structure for Problems 1-4
1. How many records does the file contain? How many fields are there per record?
There are 5 filds, each with 7 records
2. What problem would you encounter if you wanted to produce a listing by city? How would you solve this problem by altering the file structure? Some of the project managers are mentioned several times, that would cause duplication in the city database.
3. If you wanted to produce a listing of the file contents by last name, area code, city, state, or zip code, how would you alter the file structure?
Divide address capabilities, by dividing MANAGER_ADDRESS into its component parts (MGR_STREET, MGR_CITY, MGR_STATE, and MGR_ZIP), Same for MANAGER :MGR_LASTNAME, MGR_FIRSTNAME, and MGR_INITIAL, For example, creating a phone directory is easy when you can sort by last name, first name, and initial. Also by dividing the phone number into area code and number, we would be able to obtain an area code.
4. What data redundancies do you detect? How could those redundancies lead to anomalies?
Ms. Paker phone number and address also occur three times. If Ms. Parker moves and/or changes her phone number, these changes must be made more than once and they must all be made correctly. The same problems exist for the multiple occurrences of George F. Dorts.
5. Identify and discuss the serious data redundancy problems exhibited by the file structure shown in Figure P1.5.
FIGURE P1.5 The File Structure for Problems 5-8
project Name, Project #, Employee number, Job Table, Job Code : employee June H. Sattlemeier is deleted from the file, you also lose information about the existence of the JOB_CODE = EE, its hourly charge of $85.00, and the PROJ_HOURS = 17.5. The loss of the PROJ_HOURS value will ultimately mean that the Coast project is not charged properly, thus causing a loss of PROJ_HOURS*JOB_CHG_HOUR =
FIGURE P1.1 The File Structure for Problems 1-4
1. How many records does the file contain? How many fields are there per record?
There are 5 filds, each with 7 records
2. What problem would you encounter if you wanted to produce a listing by city? How would you solve this problem by altering the file structure? Some of the project managers are mentioned several times, that would cause duplication in the city database.
3. If you wanted to produce a listing of the file contents by last name, area code, city, state, or zip code, how would you alter the file structure?
Divide address capabilities, by dividing MANAGER_ADDRESS into its component parts (MGR_STREET, MGR_CITY, MGR_STATE, and MGR_ZIP), Same for MANAGER :MGR_LASTNAME, MGR_FIRSTNAME, and MGR_INITIAL, For example, creating a phone directory is easy when you can sort by last name, first name, and initial. Also by dividing the phone number into area code and number, we would be able to obtain an area code.
4. What data redundancies do you detect? How could those redundancies lead to anomalies?
Ms. Paker phone number and address also occur three times. If Ms. Parker moves and/or changes her phone number, these changes must be made more than once and they must all be made correctly. The same problems exist for the multiple occurrences of George F. Dorts.
5. Identify and discuss the serious data redundancy problems exhibited by the file structure shown in Figure P1.5.
FIGURE P1.5 The File Structure for Problems 5-8
project Name, Project #, Employee number, Job Table, Job Code : employee June H. Sattlemeier is deleted from the file, you also lose information about the existence of the JOB_CODE = EE, its hourly charge of $85.00, and the PROJ_HOURS = 17.5. The loss of the PROJ_HOURS value will ultimately mean that the Coast project is not charged properly, thus causing a loss of PROJ_HOURS*JOB_CHG_HOUR =