An ERD has m number of entities (strong, weak, parent, child all combined) andn number of relationship types (of all possible kinds). When transformed to the relational schema, Database designer come up with a solution which contained more than m+n relations. What could possibly be the reason? If you think the designer did a mistake then you can say that in your answer. Explain your answer if you think that will help. Answer:

An ERD has m number of entities (strong, weak, parent, child all combined) andn number of relationship types (of all possible kinds). When transformed to the relational schema, Database designer come up with a solution which contained more than m+n relations. What could possibly be the reason? If you think the designer did a mistake then you can say that in your answer. Explain your answer if you think that will help. Answer:

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

See similar textbooks

Similar questions

The database used for this question is a very simple one with the following schema: (Primary keys are bold, foreign keys are underlined) CUSTOMER (CustID, FirstName, LastName, City, Phone, Email) INVOICE (InvoiceNumber, CustID, Date) INVOICE_ITEM(InvoiceNumber, ItemNumber, Quantity) ITEM (ItemNumber, ItemName, UnitPrice) When a customer makes a purchase, an invoice is created. The invoice may be for many items. For example, in a single purchase, a customer might buy 10 Back Scratchers, 4 Hair Removers and a Dog Lead. Provide relational algebra (NOT SQL) queries to find the following information. NOTE: You can use the symbols s, P, etc., or the words’ PROJECT’, ‘RESTRICT’ etc. as you prefer. You do not need to try to make efficient queries – just correct ones. Where you use a join, always show the join condition. List the dates on which Homer Griffin made purchases. List the first and last names of customers who have bought “Back Scratcher” or “Hair Remover” List the first…
Translate the following ER Diagram into relational model. Show different relations that will result in addition to their attributes, PKs and FKs. Newspaper AK newsPaperID newsPaperName newsPaperAddress Work for Actor Joumalist AK actorID AK journalistID -interview- firstName journalistName lastName dateOFbirth nationality write Edition Article -publishedIN- AK editionID PK articlelD editionDate article Title related To Topic AK topicID topicWording
Answer in Sql - ER diagram in database tables.
Given the database schema with the following relations: STUDENT (id_stud, name_stud) LECTURER (id_lect, name_lect) SUBJECT (id_subject, id_lect, name_subject, credits, id_room) ROOM (id_room, no_room) ENROLL (id_stud, id_subject) Create an algebraic relation for: a. Displays all names of lecturers who teach the subject with a total of 4 credits b. Displays all no_room with the student name "Eko" c. Displays all data in the form of student id, student name, name of the course followed and the name of the lecturer who taught the subject name "Database" From the database schema and the questions above, create an appropriate SQL query for each of these statements above.
Produce a relational schema diagram that corresponds to the linked ER diagram for a database for the television show Saturday Night Live (SNL). Your relational schema diagram should include primary and foreign keys. Often-times in database system development, requirements will change after the conceptual data model has been drafted: in your rela- tional schema diagram, add the following three additional attributes: attribute “birth.date" for the relation schema Host; attribute “start.date" for the relation schema Writer; and attribute “salary" for relation schema Cast Member. Please refer back to the requirements in Question 6, for additional details that may constrain the design of the relational schema model. Use the tool linked to create an image. Hints: please carefully note that "rerun date", “address", and “phone" are multi-valued attributes; how would those be depicted in the relational schema diagram? Also, please carefully note the many-to-many relationships; how would those…
It is essential to discuss the various database table possibilities when dealing with subtype associations.Decide on a format, and then talk on the issues that should be addressed in it.
Suppose that A and B are two sets of entities connected by a relation R that has multiple one-to-one occurrences (see Figure 1). Think about a scenario in which R's generated connection is coupled with A's. SQL allows null values for attributes that are a part of a foreign key constraint. Give an example of how non-null constraints may be used in SQL to place a restriction on how much A can be involved in R.
Swing Jazz Club ERD Problem Follow the Simple Procedure for ERD diagramming to design an ERD using the following user provided information. Remember the ERD will eventually turn into the design for a database from a top down view. Make sure you resolve any many to many conflicts. Label an identifier or primary key and all pertinent attributes given. If an attribute is not readily apparent from the user information, then make one up that makes sense for the particular entity. Therefore, all entities should end up with at least an identifier and another attribute that makes sense. You may use any of the approaches shown by the book, though the ER-Model and Crow’s foot are the most common. Make sure you show entities, relationships, cardinality, and optionality. Swing Jazz Club The Swing Jazz Club teaches swing and jazz dancing and offers both private and group lessons. Swing Jazz charges $60 dollars per hour for a private lesson and $10 dollars per hour for a group lesson.…
Don't copy again and again that is wrong. Please help me with this question.
Please Slove it . Thank you so much