The file structure for Problems 1-4 FIGURE P1.1 sss 00 Cengage Leaming O 2015 Gi
ID: 3872990 • Letter: T
Question
The file structure for Problems 1-4 FIGURE P1.1 sss 00 Cengage Leaming O 2015 Given the file structure shown in Figure P1.1, answer Problems 1-4 1. How many records does the file contain? How many fields are there per record? 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? 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? What data redundancies do you detect? How could those redundancies lead to anomalies? 4. The file structure for Problems 5-8 FIGURE P1.5 133 653-234-3245 162 653-234-1123 14 3 615-233-5588 198 653-234 3254 175 905-554-7812 11 5 615-233-5568 Hurricane 1 Hurricane 2 Const 105 David F. Schwann CT 110 Ame R.Ramores C 8000 6000 5.00 101 John D Newson EE 100 JreH Stener 110 Arne R Ramoras CT 105 David F.Schwann CT Satelite 3 Satelite 26 00 05 00 91 615-233-5432 3 Satelite 112 Aleca R. Snr, Cengage Leaming 02015 5. Identify and discuss the serious data redundancy problems exhibited by the file structure shown in Figure P1.5 6. Looking at the EMP NAME and EMP PHONE contents in Figure P1.5, what changels) would you recommend? 7. Identify the various data sources in the file you examined in Problem5. 8· Given your answer to Problem 7, what new files should you create to help eliminate the data redundancies found in the file shown in Figure P1.5?Explanation / Answer
1.
File contains 7 records. Each record has 5 fields.
2.
For producing a listing grouped by city, we need the city column seperately, as the current address columns contain the city inside it, Two addresses in the same city can not be compared to true..
For overcoming, we should break the table to have one column for city seperately.
3 For producing listing as per lastName, areacode, we must break the table to respecive fields:
The new file structure would be:
project_code, first_name, last_name, area_code, city, state, zip_code
4.
Currently for 2 different projects, such as 21-5Z and 25-9T, Holly is the manager. If we want to update or any details associated to Holly, we must ensure that we update all the rows containing that data.. Like here, for Holly, the address is duplicated on both the rows, hence data redundancy. Also, if anybody forgets to update data in one row, it will lead to data inconsistency.
5.
Proj_names are duplicates, which are not required, as proj_num is present. Similarly, JOB_CHG_HOUR is also duplicated. Also, there is no primary key column in the table.
6. The employees should be moved to a seperate table containing only employees information.
7.
Projects, Job_rates
8.
Projects, Employees, Employees_in_projects, job_rates
9.
Teacher's first name and last names may not be in sync for all the available rows.
Similarly Teacher Initials are also duplicated.
10.
If we delete building KOM, then the rows containing KOM will be deleted from table. If notice carefully, Teacher Cordoza only teaches in this building only, Hence once building is removed, the teacher will also not exist in the table which is wrong.. Teacher should remain in system, while the buildings may be added or deleteed.
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