Question $3(6$ Points$)$:

Given the following database instance, answer questions $3\mathrm{.}1$ through $3\mathrm{.}3$:

Employee Plan

emp$\_$code emp$\_$lname job$\_$code plan$\_$code plan$\_$description

EC$14$ Rudell JC$21$ Term Life

EC$15$ McDade JC$12$ Stock Purchase

EC$16$ Ruellardo JC$13$ Long$-$term disability

EC$17$ Smith JC$34$ Dental

EC$20$ Smith JC$2$

Job Benefit

job$\_$code job$\_$description emp$\_$code plan$\_$code

JC$1$ Clerical EC$153$

JC$2$ Technical EC$161$

JC$2$ DBA EC$171$

JC$3$ Manager EC$173$

EC$174$

Extra$\_$Benefit EC$203$

job$\_$code plan$\_$code

JC$32$

Assume that the following attributes are the primary keys for the tables:

emp$\_$code is the primary key for Employee table

job$\_$code is the primary key for the Job table

plan$\_$code is the primary key for the Plan table

emp$\_$code, plan$\_$code is a composite primary key for the Benefit table

job$\_$code, plan$\_$code is the composite primary key for the Extra$\_$Benefit table

$$

$3\mathrm{.}1)(2$ Points$)$ Do all tables exhibit entity integrity? Answer yes or no and then explain your answer for each table

Table Entity Integrity

$($Yes$/$No$)$ Explanation

Employee

Job

Plan

Benefit

Extra$\_$Benefit

$3\mathrm{.}2)(2$ Points$)$ For each table in the database, identify foreign key$($s$)($if any$).$ For each foreign key, state the referencing relation and the referenced relation.

Referencing Relation Foreign Key Referenced Relation

$3\mathrm{.}3)(2$ Points$)$ Do all tables exhibit referential integrity? Answer yes or no and then explain your answer for each table.

Table Referential Integrity $($Yes$/$No$)$ Explanation

Employee

Job

Plan

Benefit

Extra$\_$Benefit