Modern Database Management
13th Edition
ISBN: 9780134773650
Author: Hoffer
Publisher: PEARSON
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Textbook Question
Chapter 2, Problem 2.20RQ
For the Manages relationship in Figure 2-12a, describe one or more situations that would result in different cardinalities on the two ends of this unary relationship. Based on your description for this example, do you think it is always clear simply from an E-R diagram what the business rule is that results in certain cardinalities? Justify your answer.
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b. Draw an Entity Relationship diagram from each of the following descriptions. Include the attributes, primary keys (underlines) and the relationships in the diagram (like relationship in Access).
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Draw an Entity Relationship Diagram (ERD) using Unified Modelling Language (UML) notationaccording to the below business rules. Your design should be at the logical level – include primaryand foreign key fields and remember to remove any many-to-many relationships.Sheep farm feed supplier business rules:• All entities must have surrogate primary keys.• A contact person represents one or more suppliers, and each supplier has exactly onecontact person.• A supplier supplies many feed products, and every feed product can be supplied by manysuppliers.• Each feed product belongs to a specific feed type, and many feed products can have thesame feed type.
Chapter 2 Solutions
Modern Database Management
Ch. 2 - Define each of the following terms: entity type...Ch. 2 - Match the following terms and definitions....Ch. 2 - Contrast the following terms: stored attribute;...Ch. 2 - Prob. 2.4RQCh. 2 - Prob. 2.5RQCh. 2 - Prob. 2.6RQCh. 2 - State six general guidelines for naming data...Ch. 2 - Prob. 2.8RQCh. 2 - Prob. 2.9RQCh. 2 - State three conditions that suggest the designer...
Ch. 2 - List the four types of cardinality constraints,...Ch. 2 - Give an example, Other than those described in...Ch. 2 - What is the degree of a relationship? List the...Ch. 2 - Give an example (Other than those described in...Ch. 2 - Give an example of each of the following, other...Ch. 2 - Give an example of the use of effective (or...Ch. 2 - State a rule that says when to extract an...Ch. 2 - Prob. 2.18RQCh. 2 - In addition to explaining what action is being...Ch. 2 - For the Manages relationship in Figure 2-12a,...Ch. 2 - Explain the distinction between entity type and...Ch. 2 - Why is it recommended that every ternary...Ch. 2 - A cellular operator needs a database to keep track...Ch. 2 - Prob. 2.24PAECh. 2 - Answer the following questions concerning Figure...Ch. 2 - Prob. 2.26PAECh. 2 - You may have been assigned a CASE or a drawing...Ch. 2 - Consider the two E-R diagrams in Figure 2-25 Q,...Ch. 2 - Prob. 2.29PAECh. 2 - Are associative entities also weak entities? Why...Ch. 2 - Because Visio does not explicitly show associative...Ch. 2 - Figure 2-26 shows a grade report that is mailed to...Ch. 2 - Prob. 2.33PAECh. 2 - The Is Married To relationship in Figure 2-12a...Ch. 2 - Figure 2-27 represents a situation of students who...Ch. 2 - Figure 2-28 shows two diagrams (A and B), both of...Ch. 2 - Prob. 2.37PAECh. 2 - Review Figure 2-8LQ and Figure 2-22. Identify any...Ch. 2 - Prob. 2.39PAECh. 2 - Prob. 2.40PAECh. 2 - Prob. 2.41PAECh. 2 - Prob. 2.42PAECh. 2 - Prob. 2.43PAECh. 2 - Prob. 2.44PAECh. 2 - Prob. 2.45PAECh. 2 - Prob. 2.46PAECh. 2 - Prob. 2.47PAECh. 2 - Prob. 2.48PAECh. 2 - Draw an ERD for the following situation. (State...Ch. 2 - Prob. 2.50PAECh. 2 - Prob. 2.51PAECh. 2 - Review your answer to Problem and Exercise 2-49 if...
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- For the Manages relationship in Figure 2-12a, describe one or more situations that would result in different cardinalities on the two ends of this unary relationship. Based on your description for this example, do you think it is always clear simply from an E-R diagram what the business rule is that results in certain cardinalities? Justify your answerarrow_forwardAnalyze the given entity relationship diagram and answer the following questions. What is the degree of “has” relationship?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
- Give a simple example of an E-R diagram for each concept and then write the business rules for each example. associative entity weak entity unary relationshiparrow_forwardUsing the use case diagram draw a Rich Picture and Entity Relationship Diagram.arrow_forwardPlease draw the ER diagram. Explain how you know which one is entity, attribute, and all constraints. Explain each step of the diagram.arrow_forward
- Draw an Entity Relationship Diagram (ERD) using Unified Modelling Language (UML) notation according to the below business rules. Your design should be at the logical level – include primary and foreign key fields and remember to remove any many-to-many relationships. Business rules for hairdressers: 1. All entities should have surrogate primary keys. 2. Each hairdresser can work at multiple different salons over time, and every salon employs many different hairdressers. 3. The job title of a hairdresser at a specific salon must be stored in the database. 4. The name and surname of each hairdresser must be stored in the database. 5. The name of each salon must be stored in the database. 6. Every hairdresser is certified to have several different skills, and each skill can be mastered by many different hairdressers. 7. The name of each skill must be stored in the database. 8. The date that a specific hairdresser was certified to have a specific skill must be stored in the database.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_forwardWhat exactly does it imply when we talk about the weak entity type? What exactly is the key? Please provide an example. What exactly is meant by the term "alternative specialisation"?Where exactly do I fit into the ER diagram? Provide an illustration, then draw a diagram that corresponds to it.arrow_forward
- Consider the scenario described by the statement "A customer can make many payments, but each payment is made by only one customer." Use this scenario as the basis for an entity relationship diagram (ERD) representation.arrow_forwardConstruct an Entity Relationship Diagram (ERD) in Crow’s Foot Notation for the following Nationwide City Express shipping system. Be certain to indicate identifiers and cardinality constraints. You may state any assumptions that you make. Nationwide City Express (NCE) prides itself on having up-to-date information on the processing and current location of each shipped item. To do this, NCE relies on a company-wide information system. Shipped items are the heart of the NCE product tracking information system. Shipped items can be characterized by item number (unique), weight, dimensions, insurance amount, destination, and final delivery date. Shipped items are received into the NCE system at a single retail center. Retail centers are characterized by their type, uniqueID, and address. Shipped items make their way to their destination via one or more standard NCE transportation events (i.e., flights, truck deliveries). These transportation events are characterized by a unique…arrow_forwardThe cardinality ratio depends on the real-world meaning of the entity types involved and is defined by the specific application. For the binary relationships below, suggest the cardinality ratios based on your understanding. Clearly state any assumptions you make. # Entity 1 Cardinality Ratio Entity 2 1 Student Social Security No. 2 Student Teacher 3 Classroom Wall 4 Course Text Book 5 Class Instructorarrow_forward
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Enhanced Entity Relationship Model; Author: Data Science Center;https://www.youtube.com/watch?v=ocQUtXPumdQ;License: Standard YouTube License, CC-BY