Consider the following relation schemas:   Department (dnumber, dname, employee_count), PK: dnumber. Employee (eid, fname, lname, salary, dno), PK: eid, FK: dno refs Department.   Write triggers in PL/SQL that satisfy the following requirements:   The employee_count column in the Department table records the current number of employees in each department.  You should guarantee that, whenever an employee record is inserted, deleted or updated in the Employee table, the employee_count attribute always has the correct value for the affected department(s) in the Department table.    Also, no department in the organization should have an average salary lower than 10,000.  When the insertion, deletion or update of an employee record causes the average salary of a department to be lower than 10,000, the corresponding operation should be cancelled.     You may create additional tables or views if needed.   Note that your triggers will be graded based on both correctness and efficiency.

Database System Concepts
7th Edition
ISBN:9780078022159
Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan
Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan
Chapter1: Introduction
Section: Chapter Questions
Problem 1PE
icon
Related questions
Question

Consider the following relation schemas:

 

Department (dnumber, dname, employee_count), PK: dnumber.

Employee (eid, fname, lname, salary, dno), PK: eid, FK: dno refs Department.

 

Write triggers in PL/SQL that satisfy the following requirements:

 

The employee_count column in the Department table records the current number of employees in each department.  You should guarantee that, whenever an employee record is inserted, deleted or updated in the Employee table, the employee_count attribute always has the correct value for the affected department(s) in the Department table. 

 

Also, no department in the organization should have an average salary lower than 10,000.  When the insertion, deletion or update of an employee record causes the average salary of a department to be lower than 10,000, the corresponding operation should be cancelled.  

 

You may create additional tables or views if needed.

 

Note that your triggers will be graded based on both correctness and efficiency. 

Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 3 steps

Blurred answer
Knowledge Booster
SQL Query
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, computer-science and related others by exploring similar questions and additional content below.
Similar questions
Recommended textbooks for you
Database System Concepts
Database System Concepts
Computer Science
ISBN:
9780078022159
Author:
Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan
Publisher:
McGraw-Hill Education
Starting Out with Python (4th Edition)
Starting Out with Python (4th Edition)
Computer Science
ISBN:
9780134444321
Author:
Tony Gaddis
Publisher:
PEARSON
Digital Fundamentals (11th Edition)
Digital Fundamentals (11th Edition)
Computer Science
ISBN:
9780132737968
Author:
Thomas L. Floyd
Publisher:
PEARSON
C How to Program (8th Edition)
C How to Program (8th Edition)
Computer Science
ISBN:
9780133976892
Author:
Paul J. Deitel, Harvey Deitel
Publisher:
PEARSON
Database Systems: Design, Implementation, & Manag…
Database Systems: Design, Implementation, & Manag…
Computer Science
ISBN:
9781337627900
Author:
Carlos Coronel, Steven Morris
Publisher:
Cengage Learning
Programmable Logic Controllers
Programmable Logic Controllers
Computer Science
ISBN:
9780073373843
Author:
Frank D. Petruzella
Publisher:
McGraw-Hill Education