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EBK DATABASE CONCEPTS
7th Edition
ISBN: 9780133777840
Author: AUER
Publisher: VST
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Expert Solution & Answer
Chapter 4, Problem 4.14RQ
Explanation of Solution
Relationship:
An association between several entities is termed as relationship.
- It is used to link the attributes in entities.
- It is represented in a “diamond” box with name of the relationship in Entity-Relationship diagram.
The following diagram demonstrates the “relationship” among entities.
Degree of relationship:
Degree of relationship is a number of entity classes that participate in a relationship. The relationship can be divided into two ways based on the degree of the relationship...
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Chapter 4 Solutions
EBK DATABASE CONCEPTS
Ch. 4 - Prob. 4.1RQCh. 4 - Prob. 4.2RQCh. 4 - Prob. 4.3RQCh. 4 - What is a use case, and what is its purpose?Ch. 4 - Give an example of a data constraint.Ch. 4 - Prob. 4.6RQCh. 4 - Define the term entity, and give an example other...Ch. 4 - Explain the difference between an entity class and...Ch. 4 - Define the term attribute, and give examples for...Ch. 4 - Define the term identifier, and indicate which...
Ch. 4 - Prob. 4.11RQCh. 4 - Prob. 4.12RQCh. 4 - Prob. 4.13RQCh. 4 - Prob. 4.14RQCh. 4 - List and give an example of the three types of...Ch. 4 - Prob. 4.16RQCh. 4 - Prob. 4.17RQCh. 4 - Prob. 4.18RQCh. 4 - Define the term weak entity, and give an example...Ch. 4 - Explain the ambiguity in the definition of the...Ch. 4 - Define the term associative entity, and give an...Ch. 4 - Define the terms supertype, subtype, and...Ch. 4 - What is an exclusive subtype relationship? Give an...Ch. 4 - What is an inclusive subtype relationship? Give an...Ch. 4 - Prob. 4.25RQCh. 4 - Prob. 4.26RQCh. 4 - Prob. 4.27RQCh. 4 - Prob. 4.28RQ
Knowledge Booster
Similar questions
- Give an example of each of the following, other than those described in this chapter, and clearly explain why your example is this type of relationship and not of some other degree.a. ternary relationshipb. unary relationshiparrow_forwardBy giving an example, define the following terms: A. Coding B. Relation and Relationshiparrow_forwardExplain entity sets.arrow_forward
- ER model relationships are represented using a.) relationship keys b.) primary keys c.) crows foot symbols d.) main keys What do the cardinalities in an ER model show, (please select all that apply)? a.) only a one to one relationship. b.) the minimum number of entities that can be involved in a relationship. c.) only a many to many relationship.arrow_forwardGive an example of one to one and one to many relationship?arrow_forwardGive an example of a ternary relationship (different from any example presented herein).arrow_forward
- Define a one-to-many relationship.arrow_forwardDraw an Entity Relationship Diagram for all of those below. (a simple one) Each lecturer is identified by a unique number, name and phone. A lecturer teaches several courses, and for each course there is a unique code and title (not necessarily unique). There might be several lecturers in a course. Each course requires one or more text books. Each text book is used in at least one course. A text book is identified by a unique ISBN, and its title, authors, publisher and year of publication are known. Each course has a unique code. The bank has many customers. Every customer has at least one account with the bank. An account may be shared by several customers. Each customer has a unique number, type, the opening date and the balance. A flight carries many passengers on a specific airplane. Each airplane has a unique number, while each flight has a code (unique), destination and origin. A passenger has a name, passport number and nationalityarrow_forwardGiven the following ERD. ID name salary Instructor Grades teaches ID name salary Student 1) What is the descriptive attribute of the relationship between instructor and student? 2) Is this relationship a one-to-one, a one-to-many, or a many-to-many relationship?arrow_forward
- please explain elaboratlyarrow_forwardConsider the following relation. Instructor (ID , name, dept – name, salary) Department (dept – name , building ,budget) Classroom (building , roomno , capacity ) Teaches (ID , course – id , sec – id , semesters ) Course (course – id , title , dept – name , credit ) Student (ID , name dept – name ,fot – ored ) Takes (ID , course – id , sec – id, semester , year, grade) Write down queries expressed in SQL. 1) Find the name of all instructors who got the highest salary in their department. 2) Find the names of all the students whose total credits are greater than 100. 3) Find the course id and grades of all courses taken by any student. 4) Find all departments that have at least one instructor, and list – the name of the departments along with the number of instructorarrow_forwardWrite the business rules that are reflected in the ERD shown in Figure P2.15. (Note that the ERD reflects some simplifying assumptions. For example, each book is written by only one author. Also, remember that the ERD is always read from the “1” to the “M” side, regardless of the orientation of the ERD components.) FIGURE P2.15 THE CROW’S FOOT ERD FOR PROBLEM 15arrow_forward
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