Draw the E/R diagrams for the following business rules using Gliffy. Recognize all entities, attributes, relationships, primary keys, cardinalities and constraints where suitable. Each complete entity (comprising all attributes and primary key) receives one point and each relationship (labeled with cardinalities in both directions) receives one point. Any constraint used correctly, receives two points.
Make sure your diagrams are clear and easy to read - print two diagrams or less per page – don’t comprise the business rules in the printout of your diagrams. Include your typed name and section on all pages. Professional quality is expected.
problem 1: A laboratory has several chemists who work on one or more projects. Chemists might also use certain types of equipment on each project. Data tracked for the chemist includes employee ID, name, and phone. Equipment attributes comprise a serial number and cost. Project information is tracked for a project ID and start date. When a piece of equipment is assigned to a chemist working on a specific project, the assignment date is recorded. The chemist must be assigned to at least one project and one equipment item. A given piece of equipment need not be assigned and a given project need not be assigned either a chemist or an equipment item.
problem 2: A hospital has a large number of registered physicians which comprises a physician ID and speciality. Patients are admitted to the hospital by physicians. The hospital tracks the patient ID and name. Any patient who is admitted should have exactly one admitting physician. A physician might optionally admit any number of patients. Once admitted, a given patient should be treated by at least one physician. A particular physician might treat any number of patients or might not treat any patients. Whenever a patient is treated by a physician, the hospital records the details of the treatment. Components of treatment detail comprise date, time and results.
problem 3: An art museum owns a big volume of works of art. Each work of art is describeed by an item code, title, type and size; size is further composed of height, width, and weight. A work of art is developed by an artist; however the artist for some works is unknown. An artist ID, name, date of birth and date of death (which is null for living artists) is recorded for each artist. Only data about artists for works currently owned by the museum are kept in the database. At any point in time, the status of a work of art is either on display at the museum, held in storage, away from the museum as part of a traveling show, or on loan to the other gallery. If on display at the museum, the art's location in the museum is recorded. If the art work is in storage, storage date and return date from storage are recorded. A traveling show is describeed by a show ID, the city in which the show is currently appearing and the start and end dates of the show. Most of the museum works might be part of a given show and only active exhibits with at least one museum work of art need be represented in the database. Lastly, the museum wants to retain a complete history of loaning a work of art to other galleries; a gallery ID, name and city are recorded for other galleries. Each time a work of art is loaned, the museum wants to record the date the work was loaned and the date it was returned.
problem 4: A technology company gives offerings to its customers. Offerings are of two kinds; products and services. Offerings are recognized by an ID and description. In addition, products are describeed by product name, standard price and date of first release; services are describeed by name of the company's unit responsible for the service and conditions of the service. There are repair, maintenance and other kinds of services. A repair service has a cost and is the repair of some product; a maintenance service has an hourly rate.
Fortunately, some products never require repair. Though, there are many potential repair services for a product. The customer might purchase an offering and the company needs to keep track of when the offering was purchased and the contact person for that offering with the customer. Unfortunately, not all offerings are purchased. Customers are recognized by an ID, name, address and phone. When a service is performed, that service is billed to a customer. As some customers purchase offerings for their clients, a customer might be billed for services he or she did not purchase, and also for ones that were purchased.
When a customer is billed for a service (though some might never require a service of any type), the company requires to keep track of the date the service was performed, the date the bill is due, and the amount due.
problem 5: PROJECTS INC., is an engineering firm with around 500 employees. A database is needed to keep track of all employees, their skills, projects assigned and departments worked in. Every employee has a unique number assigned by the firm, needed to store his or her name and date-of-birth. If an employee is currently married to the other employee of Projects, Inc., the date of marriage and who is married to whom must be stored; though, no record of marriage is needed if an employee’s spouse is not also an employee. Each employee is given a job title (for illustration, engineer, admin assistant, foreman, and so forth).
We are interested in collecting more data specific to engineers and admin assistants. The relevant data to be recorded for engineers is the kind of degree (ex: electrical, mechanical, civil, and so on); for admin assistants, it is their typing speed.
An employee does only one kind of job at any given time, and we only need to retain information for an employee’s current job. There are 11 different departments, each with a unique name. An employee can report to only one department. Each department has a phone number.
To procure different kinds of equipment, each department deals with many vendors. A vendor typically supplies equipment to many departments. We are needed to store the name and address of each vendor.
Most of the employees can work on a project. An employee can work in many projects (for illustration, Southwest Refinery, California Petrochemicals and so forth) however can only be assigned to at most one project in a given city. For each city, we are interested in its state and population. An employee can have lots of skills (preparing material requisitions, checking drawings and so forth), however (s)he might use only a given set of skills on a particular project. (For illustration, employee MURHPY may prepare requisitions for Southwest Refinery project and prepare requisitions and also check drawings for California Petrochemicals.) Employees use each skill which they possess in at least one project. Each skill is assigned a number, and we should store a short description of each skill. Projects are distinguished by project numbers and we must store the estimated cost of each and every project.