DATABASE MANAGEMENT SYSTEMS - PLEASE ANSWER ALL OF THE FOLLOWING QUESTIONS IN TH
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Question
DATABASE MANAGEMENT SYSTEMS - PLEASE ANSWER ALL OF THE FOLLOWING QUESTIONS IN THE PICTURES POSTED BELOW:
Given the following database instance, answer questions 1.1 through 1.3 Employee Plan EC14 EC15 EC16 EC17 EC20 JC2 JC4 JC1 JC3 JC2 Term Life Stock Purchase Long-term disabil Dental Extra Vacation McDade Smith Smith Job Benefit JC1 JC2 JC4 JC3 Clerical Technical DBA Manager EC15 EC16 EC17 EC17 EC17 EC20 4 code an code Assume that the following attributes are the primary keys for the tables: emR .code is the primary key for Employee table ioh sode is the primary key for the Job table lan .sedk gmR.cede nan..Sede is a composite primary key tor the Benetit table iob cods, plan code is the composite primary key for the Extra Benefit table is the primary key for the Plan table 1.1 (2 Points) Do all tables exhibit entity integrity? Answer yes or no and then explain your answerExplanation / Answer
Please Note: I have answered the first question and all of its sub-parts, as per Chegg Answering Guidelines. Please Re-Post for the answers to the other Questions.
Q1.
Answers)
1.1 (2 Points) Do all tables exhibit entity integrity?
Answer)
No.
Entity integrity of a table is its ability to maintain primary keys. The primary key should be unique to a table and also it should not match the primary key of any other row in the table.
Here,
emp_code - primary key for Employee table
job_code - primary key for the Job table
plan_code - primary key for the Plan table
emp_code, plan_code - composite primary key for the Benefit table
job_code, plan_code - composite primary key for the Extra_Benefit table
Here in Plan table, entity integrity is not maintained and void as plan_code primary key values repeat.
1.2 (3 Points) For each table in the database, identify the foreign key(s) (if any). For each foreign key, state the referencing relation and the referenced relation (USE THE TABLE LAYOUT FROM POWER POINT SLIDE 19, IN LECTURE 2)
Answer)
Employee table - job_code is a foreign key which references the job_code column of Job table
Benefit table - emp_code and plan_code are foreign keys. emp_code references Employee - emp_code. plan_code references Plan - plan_code.
Extra_Benefit table - job_code and plan_code are foreign keys. plan_code references Plan - plan_code. job_code references Job - job_code.
1.3 (2 Point) Do all tables exhibit referential integrity? Answer yes or no (for each table) and then explain your answer.
Answer)
No.
Referential integrity means primary key and foreign key relationships.
Employee table has a primary key and foreign key relationships.
Benefit table has a primary key and foreign key relationships.
Extra_Benefit table has a primary key and foreign key relationships.
Plan and Job table do not exhibit referential integrity as there is no primary key and foreign key relationship.
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