Concept explainers
Figure 2-27 represents a situation of students who attend and work in schools and who also belong to certain clubs that are located in different schools. Study this diagram carefully to try to discern what business rules are represented.
Figure 2-27 E-R diagram for Problem and Exercise 2-35
- You will notice that cardinalities are not included on the Works For relationship. State a business rule for this relationship, and then represent this rule with the cardinalities that match your rule.
- State a business rule that would make the Located In relationship redundant (i.e., where the school in which a club is located can be surmised or derived in some way from other relationships).
- Suppose a student could work for only a school the student attends but might not work. Would the Works For relationship still be necessary, or could you represent whether a student works for the school she attends in some other way (if so, how)?
- Based on the rules of the ERD in Figure 2-27, is it possible for a student to belong to a club located in a school that the student does not attend? Explain.
- Is it possible to determine which schools do not have any of their students belonging to any club in that school? Explain.
Want to see the full answer?
Check out a sample textbook solutionChapter 2 Solutions
Pearson eText for Modern Database Management -- Instant Access (Pearson+)
Additional Engineering Textbook Solutions
Concepts Of Programming Languages
Starting Out with Java: From Control Structures through Data Structures (3rd Edition)
Starting Out with Java: From Control Structures through Objects (7th Edition) (What's New in Computer Science)
Computer Science: An Overview (12th Edition)
Java: An Introduction to Problem Solving and Programming (7th Edition)
Differential Equations: Computing and Modeling (5th Edition), Edwards, Penney & Calvis
- Draw an entity-relationship diagram for the following situation:Many students play many different sports. One person, called the head coach, assumes the role of coaching all these sports. Each of the entities has a number and a name. (Make any assumptions necessary to complete a reasonable diagram. List your assumptions.)arrow_forwardDesign the Entity Relationship Diagram (ERD) showing entities, attributes, primary key and relationship cardinality for the following scenario. Any employee works for only a department and under supervision of a manager (where manager is also an employee). Employee's address, city code & city name also has been recorded. Every employee may work for multiple project, but an employee may be on vacation and not assigned to any projects. Working hour may be different for an employee for different projects. Projects are broken into tasks; A task is created for one project and assigned to one department. Requisitions are made for projects; Each requisition could ask for any number of items; Items could be: equipment item or materials item and are coded in a similar way; Each requisition is for one project and is made to one supplier. The important data fields are employee_id, employee_name ,employee_address, employee_email, department_id, department_name, location, city_code, city_name,…arrow_forwardDraw an Entity Relationship Diagram for all of those below. Draw an ER diagram to represent information about students. A student is identified by his/her student number. Student’s name (first and last), permanent address, phone number, gender and date of birth are also stored. An airplane has a registration number, type, number of economy class seats, number of business class seats and the year of production. Some students live in student halls. Each hall has a name (unique) and an address. Each student has a number (unique) and a name. Assume that there are students living in every hall. Each text book has a unique ISBN (International Standard Book Number), and contains several chapters. Each chapter has a chapter number (unique within a book), the number of pages and the number of references. A chapter covers a single topic, but the same topic may be covered in various books. Each lecturer is identified by a unique number, name and phone. A lecturer teaches several courses, and for…arrow_forward
- Draw an Entity Relationship Diagram for ther following information.arrow_forwardYou are given an E-R diagram with two entities Orders and Customers. What does the lone between the Customers entity and the Place relationship represent?arrow_forwardDraw a use case diagram based on the case study given below.Your diagram should contain at least 3actors, 8 use cases, and 2 include and 2 extend relationships. Shopping Made Easy System A customer uses Shopping Made Easy System for online shopping. System requires the customer to sign up and sign in to be able to interact with the system. Customer registration is verified by the administration. A customer may use the portal as a guest without signing up but is only able to view catalogues in case of a guest. A customer can manage his/her account which involves signup/sign in and profile management. A customer can browse through catalogues to view different products; customer can also search for a specific catalogue by name or code number. Customer can view the products and can log out without buying. Another main feature of the system is Shopping cart management. Customer can add or remove items in cart. Customer can check which items have…arrow_forward
- Prepare an E-R diagram for a real estate firm that lists property for sale. Identify all entities (supertype/subtype), attributes (optional/required), unique identifiers, relationships and relationships cardinality and optionality. Resolve any M-M relationship you find. • The firm has several sales offices in several states. Each sales office has Office_Number and a Location. • Employees are assigned to work in different sales offices. Each employee has an ID and Name. • An employee must be assigned to only one sales office. For each sales office, there is always one employee assigned to manage that office. For each manager we record the start date of the management job. • The firm lists properties for sale. Each property has an ID, description and Location. Each unit of property must be listed with one (and only one) of the sales offices. A sales office may have any number of properties listed. • Each unit of property has one or more owners. owners have ID and Name. An owner may own…arrow_forwardaccording to this Class diagram, i need you to draw Entity–relationship diagram Note : Please this diagram contains a 3 step 1-Conceptual ER 2-Logical ER 3-Physical ER Thank you :)arrow_forwardDesign a system to track advance payments made to employees. Use uml diagrams and design patterns in this system. The design steps will be as follows. Step 1 - Prepare an analysis document on the given topic. Step 2 - Create a Use case diagram for your requirement that contains at least 3 actor, 10 use case and use all relationship type Step 3 - Create an activity diagram for requirement Step 4 - Create a class diagram for all requirement that contains at least 10 class, necessary relations and types. Add the important attributes of the classes to the model. Step 5 - Use three design patterns, at least one creation, one structural, and one behavioral pattern, integrated into your classroom design. Step 6 - Code one of the design patterns you use with java. Note: The design should be homogenate. Excessive usage of any property type, object type, or function type is not suitable. For example, for creating 10 relations between classes, the number of relation types for aggregation,…arrow_forward
- Consider the following entity relationship diagram. Booking Employee Room Building • Booking ID • Employee ID • Building ID • Room ID • First Name • Room ID P • Name Description • Employee ID • Name Last Name • Date • Campus Zone • Email Address • Capacity • Start Time • Map Coordinates Phone • Bookable • End Time For each statement below, use the drop-down box to indicate whether it is true (answer 1) or false (answer2), according to the design decisions encoded in the ERD. Every booking is associated with exactly one employee. ✓ Every employee is associated with at most one booking. ✓ A building may contain no rooms that are recorded in the database. Each room may have many bookings. 1. True ✓ A room must have at least one booking. 2. False ✓ A booking can be associated with many employees. An employee may have no phone number recorded. ✓ A room must have its capacity recorded. ✓ A building is uniquely identified by its map coordinates.arrow_forwardCreate an ER DIAGRAM that shows relationship between eachother and post the picture please . An Inventory entity can be associated with zero or many Beer entities. A Beer entity can be associated with one and only one Inventory entity. An Inventory entity can be associated with zero or one Brewery entity. A Brewery entity can be associated with zero or many Inventory entities. An Employee entity can be associated with one and only one Brewery entity. A Brewery entity can be associated with zero or many Employee entities. An Employee entity can be associated with zero or many Order entities. An Order entity can be associated with one and only one Employee entity. These business rules assume that a brewery company has an inventory of beers, which are brewed by one or more breweries and supplied by one or more suppliers. The breweries employ one or more employees and can receive orders for their beers.arrow_forwardConsider the following ER diagram given to you what are the possible relations you will be creating inRelational model.arrow_forward
- Database System ConceptsComputer ScienceISBN:9780078022159Author:Abraham Silberschatz Professor, Henry F. Korth, S. SudarshanPublisher:McGraw-Hill EducationStarting Out with Python (4th Edition)Computer ScienceISBN:9780134444321Author:Tony GaddisPublisher:PEARSONDigital Fundamentals (11th Edition)Computer ScienceISBN:9780132737968Author:Thomas L. FloydPublisher:PEARSON
- C How to Program (8th Edition)Computer ScienceISBN:9780133976892Author:Paul J. Deitel, Harvey DeitelPublisher:PEARSONDatabase Systems: Design, Implementation, & Manag...Computer ScienceISBN:9781337627900Author:Carlos Coronel, Steven MorrisPublisher:Cengage LearningProgrammable Logic ControllersComputer ScienceISBN:9780073373843Author:Frank D. PetruzellaPublisher:McGraw-Hill Education