DATABASE SYSTEMS-MINDTAPV2.0
13th Edition
ISBN: 9780357427873
Author: Coronel
Publisher: CENGAGE L
expand_more
expand_more
format_list_bulleted
Concept explainers
Expert Solution & Answer
thumb_up100%
Chapter 4, Problem 1RQ
Explanation of Solution
Conditions:
Following are the conditions should be met before an entity is referred as a weak entity:
- The entity should be “existence-dependent” on its parent entity.
- If an entity is referred as an “existence-dependent”, then that entity can exist in the
database if and only if when it is related with another entity existence.
- If an entity is referred as an “existence-dependent”, then that entity can exist in the
- The entity should inherits a section of its primary key (PK) from its parent entity.
Example:
Consider the following ER diagram along with its attributes:
Explanation:
- The entity CLASS is “existence-dependent” on COURSE entity. Hence the CLASS entity uses a PK component from its parent entity (COURSE).
- The CLASS entity’s PK is (COURSE_ID, CLASS_SEC).
- In this strong implementation, the CLASS entity is referred as a weak entity between COURSE and CLASS.
Want to see more full solutions like this?
Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
What is the difference between a weak entity and a strong entity that is necessary to have a connection with another entity?
What two conditions must be met before an entity can be classified as a weak entity?Give an example of a weak entity
What are the two requirements that an entity must have in order to be classified as a weak entity?Give a specific example of a susceptible entity.
Chapter 4 Solutions
DATABASE SYSTEMS-MINDTAPV2.0
Ch. 4 - Prob. 1RQCh. 4 - What is a strong (or identifying) relationship,...Ch. 4 - Prob. 4RQCh. 4 - Suppose you are working within the framework of...Ch. 4 - Prob. 6RQCh. 4 - Prob. 7RQCh. 4 - Discuss the difference between a composite key and...Ch. 4 - What two courses of action are available to a...Ch. 4 - What is a derived attribute? Give an example. What...Ch. 4 - Prob. 11RQ
Ch. 4 - Discuss two ways in which the 1:M relationship...Ch. 4 - Prob. 13RQCh. 4 - Prob. 14RQCh. 4 - Briefly, but precisely, explain the difference...Ch. 4 - What are multivalued attributes, and how can they...Ch. 4 - Prob. 17RQCh. 4 - Prob. 18RQCh. 4 - What two attributes must be contained in the...Ch. 4 - Describe precisely the composition of the...Ch. 4 - Prob. 21RQCh. 4 - Prob. 1PCh. 4 - Create a complete ERD in Crows Foot notation that...Ch. 4 - Prob. 4PCh. 4 - Prob. 5PCh. 4 - Prob. 6PCh. 4 - Prob. 7PCh. 4 - Prob. 8PCh. 4 - Prob. 9PCh. 4 - Prob. 10PCh. 4 - Prob. 11C
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, computer-science and related others by exploring similar questions and additional content below.Similar questions
- Is there a need for creating an associative entity? If so, draw one, if not, then suggest why?arrow_forwardWhat are the two requirements that an entity must meet in order to be classified as a weak entity?Give an example of a weak or susceptible entity to illustrate your point.arrow_forwardThe difference between a weak entity set and a strong entity set should be explained.arrow_forward
- Talk about what weak and strong entity sets are.arrow_forwardWhat is NOT another name for an associative entity? Linking table Bridge entity Composite entity Strong entityarrow_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 cardinality ratios based on common-sense meaning of the entity types. Clearly state any assumptions you make. Entity 1 Student Cardinality Ratio Entity 2 Course Item Class Teacher TextBook wwwwwwwwwww Order Instructorarrow_forward
- a. Structurally-speaking, what weakens a weak entity (ie. why do we even call it 'weak')? b.How would we "strengthen" a weak entity (make it be not weak)? What specifically makes this not be weak?arrow_forwardGive Some additional examples of strong and weak entity pairs?arrow_forwardWhat distinguishes a weak entity from a strong entity required to connect with another entity is not immediately apparent.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- Database Systems: Design, Implementation, & Manag...Computer ScienceISBN:9781305627482Author:Carlos Coronel, Steven MorrisPublisher:Cengage Learning
Database Systems: Design, Implementation, & Manag...
Computer Science
ISBN:9781305627482
Author:Carlos Coronel, Steven Morris
Publisher:Cengage Learning