the descriptive property possessed by each entity set is

A weak entity is represented by a double outlined rectangle. .flex-container > div { A directory of Objective Type Questions covering all the Computer Science subjects. 1.

Questions from Previous year GATE question papers, UGC NET Previous year questions and practice sets. 1. Here you can access and discuss Multiple choice questions and answers for various competitive exams and interviews.

padding:10px; Your email address will not be published. But there are some relationships that are naturally non-binary, Replace $n$-ary relationship-set with a new entity-set $E$, Create an identifying attribute for $E$ (e.g.

A relationship is an association among several entities.

An ________ is a set of entities of the same type that share the same properties, or attributes. Course Hero, Inc. The example shows how composite attributes can be represented in the E-R notation. In the context of a database table, the statement "A___B" indicates that if you know the value of attribute A, you can look up the value of attribute B. functionally dependent on The attribute B is ___ the attribute A if each value in column A determines one and only one value in column B.

and a student is associated with several (including 0) instructors via advisor. Many-to-many necessitate forming an associative entity along with every relationship v. Many additional associative entities are created and m:n relationships is less restrictive than one-to-many vi. True False 2.When a user enters or updates information in one ERP module, it is immediately and automatically updated, Question 1. View Answer, 7. kvargli6h and 2 more users found this answer helpful. The E-R diagram expesses the overall logical structure of a database graphically. The function that an entity plays in a relationship is called that entitys _____________. 7. b) Position It would seem likely that some relationships would never be M:N; still consider M:N vii. Like strong entity, weak entity does not have any primary key, It has partial discriminator key. and a student is associated with at most one instructor via the relationship advisor. A property of an entity that can exist apart from one or more related entities. Formally, an attribute is a function that maps from the entity into a domain. a) Single valued a) NA Hence, the candidates can check the Entity Framework MCQ Quiz and learn the questions and answers. document.write(d.getFullYear()) (Multiple Choice Quiz)with very accurate answers. a) Register_number Useful in mapping the meanings and interactions of real-world enterprises onto a conceptual schema. Attribute set: c. Relation set: d. Entity model: View Answer Report Discuss Too Difficult!

Can't create a schema which uses course_id twice! are the most common relationship-sets in a database system.

In ER diagram, relationship type is represented by a diamond and connecting the entities with lines. 1 2 3 4 5 6 A set of strong entities is known as strong entity set. Which of the following schema is present at highest level ? ERM is a database modeling technique that generates an abstract diagram or visual representation of a systems data that can be helpful in designing a relational database. Find Answers To Your Multiple Choice Questions (MCQ) Easily at Thank you for visiting. A weak entity is represented by a double rectangle. 4 In an E-R, Y is the dominant entity and X is a subordinate entity. may participate as owner in an identifying relationship. c) Thing in real world involves modelling independent of the DBMS. (Points : 40)(MUST BE AT LEAST 150 WORDS), 5.

Specialization and generalization are simple inversions of each other; they are represented in an E-R diagram in the same way. Our online database trivia quizzes can be adapted to suit your requirements for taking some of the top database quizzes. Answer: Single Valued Attributes: It is an attribute with only one value.

between strong entity-sets $A$ and $B$, Primary key of relationship-set is union of all entity-set primary keys, $\textit{primary_key}(A) \cup \textit{primary_key}(B)$, Either entity-sets primary key is acceptable, $\textit{primary_key}(A)$ or $\textit{primary_key}(B)$, Primary key of entity-set on many side is primary key of relationship, Example: relationship $R$ between $A$ and $B$, One-to-many mapping, with $B$ on many side, Schema contains $\textit{primary_key}(A) \cup \textit{primary_key}(B)$, plus any descriptive attributes on $R$, $\textit{primary_key}(B)$ is primary key of $R$, Each value for $\textit{primary_key}(B)$ can appear only once in $R$, Primary key of Section is course_id, sec_id, semester, year, In cases like this, roles must be used to distinguish between the entities involved in the relationship-set, Course participates in prerequirement relationship-set twice. This set of Advanced Database Management System Multiple Choice Questions and Answers (MCQs) focuses on Data Models:Entity Relationship Model . An entity in this context is an object, a component of data. flex-wrap: wrap;

>>, What is `A m me gusta` in English? a) Entity-relationship diagram b) Entity diagram c) Database diagram d) Architectural representation Answer: a Explanation: E-R diagrams are simple and clearqualities that may well account in large part for the widespread use of the E-R model. View Answer, 5. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students. c) Date_of_birth This set of Advanced Database Management System focuses on Entity Relationship Diagram MCQs (Multiple Choice Questions and Answers ) . The relation between one strong and one weak entity is represented by a double diamond. Generalization is used to emphasize the similarities among lower-level entity sets, Permits an economy of representation, doesn't repeat shared attributes, For E-R model to be useful, need to be able to convert diagrams into an implementation schema, Big overlaps between E-R model and relational model, Biggest difference is E-R composite/multivalued attributes, vs. relational model atomic attributes, Specify any foreign key references to other relations, Strong entity-set $E$ with attributes $a_1, a_2,\ldots, a_n$, Create a relation schema with same name $E$, and same attributes $a_1, a_2,\ldots, a_n$, Primary key of relation schema is same as primary key of entity-set, Strong entity-sets require no foreign keys to other things, Every entity in $E$ is represented by a tuple in the corresponding relation, A strong entity set reduces to a schema with the same attributes, All attribute domains are atomic in the relational model, Each component attribute maps to a separate attribute in relation schema, In relation schema, simply cant refer to the composite as a whole, (Can adjust this mapping for databases that support composite types), E-R constraint on multivalued attributes: in a specific entitys multivalued attribute, each value may only appear, For a multivalued attribute $M$ in entity-set $E$, Create a relation schema $R$ to store $M$, with attribute(s) $A$ corresponding to the single-valued version of $M$, Attributes of $R$ are: $\textit{primary_key}(E) \cup A$, Primary key of $R$ includes all attributes of $R$, Each value in $M$ for an entity $e$ must be unique, Foreign key from $R$ to $E$, on $\textit{primary_key}(E)$ attributes, Given entity set Instructor with composite attribute, Each value of the multivalued attribute maps to a separate tuple on schema, Weak entity-sets depend on at least one strong entity-set, The identifying entity-set, or owner entity-set, Relationship between the two is called the identifying relationship, Weak entity-set $A$ owned by strong entity-set $B$, Attributes of $A$ are $\{a_1, a_2,\ldots, a_m \}$, Some subset of these attributes comprises the discriminator of $A$, $\textit{primary_key}(B) = \{b_1, b_2,\ldots, b_n \}$, Relation schema for $A$: $\{a_1, a_2,\ldots, a_m \} \cup \{b_1, b_2,\ldots, b_n \}$, Primary key of $A$ is $\textit{discriminator}(A) \cup \textit{primary_key}(B)$, $A$ has a foreign key constraint on $\textit{primary_key}(B)$, to $B$, Relation schema for weak entity-set already includes primary key for strong entity-set, No need to create relational model schema for the identifying relationship. Add it Herewell review your comment and contact you soon. Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries.

No attribute is permitted to have multiple data values. It will also explain the different kinds of relationships that you can define between entities in Dataverse.

The correct answer toThe descriptive property possessed by each entity set is _________ question isB. Attribute.I Recommend you to read the next question and answer, NamelyWhat is `A m me gusta` in English? We need foreign-key constraints on relation schema for $R$ ! Choose your answer and check it with the given correct answer. b) Present working model A diagrammatic representation of the data model is a very important part of designing a database schema. Use singular or plural form for naming entity-sets, but be consistent.

Entities can be associated with one another in which of the following? This type of attribute is called Link attributes of a relationship set to a relationship set. All Rights Reserved. Copyright 2010 - d) Derived attribute Products assigned to different product lines viii.

a) Entity set This preview shows page 1 - 3 out of 3 pages. The Entity-Relationship diagram gives a logical structure of the database graphically.

Weak entity is represented by double rectangle. .

can participate in relationships other than the identifying relationship. Mapping generalization/specialization to relational model is straightforward, Mapping aggregation to relational model is straightforward, Create relation schema for the relation containing. A multi-valued attribute is a single attribute with two distinct data values entered for that attribute. The relationship between the weak entity and it's owner entity sets is always a total many-to-one relationship.

For each entity-set $E_i$ participating in $R$: Relation schema for $R$ has a foreign-key constraint on $E_i$ relation, for $\textit{primary_key}(E_i)$ attributes, Relation schema notation doesnt provide mechanism for indicating foreign key constraints. An instructor is associated with several (including 0) students via advisor. Making notes on your relational model schema is a very good idea, Can specify both foreign key constraints and candidate keys in the SQL DDL, Create relation schema for higher-level entity-set, Create schemas for lower-level entity-sets. Composite attributes can be divided into subparts (that is, other attributes). Know Explanation? An ERD contains different symbols and connectors that visualize two important information: The major entities within the system scope, and the inter-relationships among these entities. What operations will be performed against the data? Different styles for entities, relationships and attributes, ER diagrams can look completely different depending on the used tool / book.

An entity set may include subgroupings of entities that are, The cardinality interval $l:h$: represents different constraints on generalizations, Lower limit $l$: 0 partial; 1 total, Upper limit $h$: 1 disjoint; * overlapping.

An entity set is a collection of similar entities. View Answer, 6. We depict a weak entity set by double rectangles. b) Attribute A relationship between two entities signifies that the two entities are associated with each other somehow. These entities can have attributes that define its properties.

Please log inor registerto add a comment. margin-bottom:5%; So we have a many-to-many relationship. a) Object of relation 0votes. A many-to-many relationship must be modeled as an associative entity when there are attributes associated with the relationship. Change names of key attributes to distinguish roles! Database Management System Certification Contest, here is complete set on 1000+ Multiple Choice Questions and Answers on Database Management System, Prev - Database Questions and Answers Tuple Relational Calculus and Domain Relational Calculus, Next - Database Questions and Answers Constraints, Certificate of Merit in Database Management System, Database Questions and Answers Entity-Relationship Diagrams, Database Questions and Answers Entity-Relationship Design Issues, RDBMS Questions and Answers Entity Relationship Model, RDBMS Questions and Answers Entity Relationship Diagrams, Oracle Database Questions and Answers Attribute, Tuple and Entity, Database Questions & Answers A Simple Transaction Model, Database Questions and Answers Database Design Process, Database Questions and Answers Extended E-R Features, Database Questions and Answers Constraints, What is iSCSI Network Portal and Network Entity, Master of Computer Applications Questions and Answers.

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