Create a Crow's Foot ERD for each of the following descriptions. (Note that the word many merely means more than one in the database modeling environment.) a. Each of the MegaCo Corporation's divisions is composed of many departments. Each department has many employees assigned to it, but each employee works for only one department. Each department is managed by one employee, and each of those managers can manage only one department at a time. b. During some period of time, a customer can download many ebooks from BooksOnline. Each of the ebooks can be downloaded by many customers during that period of time. c. An airliner can be assigned to fly many flights, but each flight is flown by only one airliner.

The Acme Company wants to construct a database to keep track of the company’s employees, departments, and projects as well as the employee’s dependents. Draw the entity-relationship model. The requirements collected to date to be modeled are:   The company is organized into departments. Each department has a name, a number, and an employee who manages the department.   A department controls a number of projects, each of which has a name, a number, and a start date but not all departments have projects assigned to them. We store each employee’s name, social security number, address, salary, sex, and birth date. Every employee is assigned to a department but may work on several projects, which are not necessarily under the control of the same department. We keep track of the number of hours per week that each employee works on each project. For most projects, a team of employees is assigned to work on the project while some employees are never assigned to a project. We also keep track…

The database used for this question is a very simple one with the following schema: (Primary keys are bold, foreign keys are underlined)   CUSTOMER (CustID, FirstName, LastName, City, Phone, Email) INVOICE (InvoiceNumber, CustID, Date) INVOICE_ITEM(InvoiceNumber, ItemNumber, Quantity) ITEM (ItemNumber, ItemName, UnitPrice)   When a customer makes a purchase, an invoice is created. The invoice may be for many items. For example, in a single purchase, a customer might buy 10 Back Scratchers, 4 Hair Removers and a Dog Lead. Provide relational algebra (NOT SQL) queries to find the following information. Each question is worth 2 marks. NOTE: You can use the symbolss, P, etc., or the words’ PROJECT’, ‘RESTRICT’etc.as you prefer. You do not need to try to make efficient queries – just correct ones. Where you use a join, always show the join condition.   List the first and last names of Customers who come from the City named Perth. List the first and last names of customers who had…

Draw the ER diagram based on the following specification. A tutorial school is using a database to manage information about teachers, courses, and students. Each teacher is identified by staff_id, has a name, an email address, and a phone number. Each student is identified by student_id, has a name, an email address, and a registration date. Each course is identified by course_id, year, and semester. In addition, each course has a name. Each course is associated with multiple lessons. A lesson has a lesson number, a location, a date, a start-time, and an end-time. Lesson numbers are sequentially numbers, starting from 1, generated separately for each course. Each teacher teaches at least one course. Each student takes at least one course. Each course is taught by one teacher. Each course can be taken by many students.