Create ERDs for the following cases. • Identify entities, identifier and attributes for each entity, and relationships between the entities. Identifiers can be represented as either PK or underline. • Define cardinalities of each relationship. • In this assignment, you don't need to define an associative entity (optional). Let me clarify that while a many-to-many relationship should be converted to an associative entity for the next step (logical data modeling), this assignment for conceptual data modeling allows you to either leave it as many-to-many or use an associative entity for it. If needed, you can make some reasonable assumptions on attributes and cardinalities of relationship. Problem 1 Create an ERD based on the following business rules for course enrollment. • Each course can have multiple sections. Multiple courses cannot be taught in the same section

Create ERDs for the following cases. • Identify entities, identifier and attributes for each entity, and relationships between the entities. Identifiers can be represented as either PK or underline. • Define cardinalities of each relationship. • In this assignment, you don't need to define an associative entity (optional). Let me clarify that while a many-to-many relationship should be converted to an associative entity for the next step (logical data modeling), this assignment for conceptual data modeling allows you to either leave it as many-to-many or use an associative entity for it. If needed, you can make some reasonable assumptions on attributes and cardinalities of relationship. Problem 1 Create an ERD based on the following business rules for course enrollment. • Each course can have multiple sections. Multiple courses cannot be taught in the same section

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

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We can convert any weak entity set to a strong entity set by simply adding appropriate attributes. Why, then,do we have weak entity sets? (a) We want to avoid the data duplication and consequent possible inconsis- tencies caused by duplicating the keyof the strong entity set.(b) Weak entities reflect the logical structure of an entity being dependent on another entity.(c) Weak entities can be deleted automatically when their strong entity is deleted.(d) All of the above.
An instructor has several phone numbers. When reducing the ER diagram down to a schema this must be addressed. Which of the following statements are true? a. an instructors phone is what is known as a multi-valued attribute b. a multi-valued attribute of an entity is expressed as a separate schema with attributes including the primary key of the original entity and the multi-valued attribute c. the instructor should have a column for each type of phone number d. multi-valued attributes must be flatted out to a separate attribute for each component
What kinds of information could you capture about this relationship? What would the new ERD look like? Would the intersection entity be considered dependent or independent? Can you think of other kinds of M:N relationships that exist in the real world? How would you resolve these M:N relationships if you were to include them on an ERD? The newly created office of the university, the Student Housing Office, helps enrolled students find apartments for them to stay in while attending school. The office asks apartment owners to fill in an information form about their units for rent that are available (location, number of bedrooms, monthly rent, utilities, curfew, kitchen, CR, distance to campus, etc.). Students needing assistance need to register with the service - they in turn can search the rental information to find apartments that meet their needs or budget. Students then can contact the owners directly to see the unit and possibly rent it. IF it gets rented, the apartment owners…
What does an associative entity model? a.) Associative entities model pure relationships rather than entities. b.) Associative entities model entities that are independent. c.) Associative entities model the real-world scenarios of ways to look up data. d.) Associative entities model attributes and how they are linked to entities.
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?
about this problem, I would like to know why there are only 6 entities and not 7 (GreenChampion must be an entity) if yes or no why? and how include it in the diagram. (I've asked this question before but I'm being answered sideways or incorrectly answers I don't know why like the diragram here). Can you please help me with real answers ? Thank you very much
Suppose that we wish to keep a genealogy. The information we wish to record about each person includes their name, date of birth, phone number, and degrees obtained . We also need to keep track of the mother, father, and children of each person. Draw a complete Entity-Relationship diagram. You must include all the details, sad as keys, weak entities (if any), cardinality constraints, etc. Your diagram must avoid redundancy.
Reference: A --> B--> C QUestion? what is the defintion of this type of relationship and what is an example of it?
For each of the following collection of entities, give the assumptions concerning the relationship between entities and attributes. EMPLOYEE(EMP_NUM, EMP_LNAME, EMP_INITIAL, EMP-DOB) DEPENDENT(EMP_NUM, DEP_NUM, DEP_FNAME, DEP_DOB)
This is the ER model for the case where there exists the entity of Product, which has the attributes of costPrice, salePrice, Identifier, factoryCode, description. These Products are manufactured by a Factory that has the attributes of description, factoryCode, factoryAddress, and this Factory sells its products to the Distributor entity, which has the attributes of distributorCode, factoryCode, email, description, distributorName. Please do the next thing: The requirement has been expanded with the following information: 'Currently, an Excel sheet is used where we store the information of the products that customers have ordered through orders; information is stored about when an order has been delivered and who or which company has made the delivery of the order.' Expand the ER diagram seen in class to comply with the new requirements requested, and also indicate what type of cardinality each of the relationships between the entities has." Please do the IMAGE E-R Diagram Expanded
Illustrate an Entity-Relationship Diagram (ERD) model using Crow’s Foot notation Here we can have the following entities 1.patients:this entity will store the details of the patients and the attributes for this entity is id(which is unique for each patient and can be used as a primary key) name(this attribute will store the name of the patient and it is a composite attribute) address(this attribute will store the address of the patient and it is multi valued attribute. ) contact_num(this is also a multi valued attribute which will store the contact details of the patient). age(which is a derived attribute) 2.room:this entity will store the information about the details of the rooms. The attributes are. id(this is unique for each room and can be used as a primary key) room number(this will store the room number) Total_bed(this will store the total number of beds present in that room) 3. Bed:this entity will store the information regarding to each bed present in an room, and the…
What does it mean to be a weak entity? Set a good example.