Description

MSDS 7330
File Organization and Database Management Homework Assignment 2
For each question, in the Homework Answer Sheet state the letter of your chosen answer and write out the explanation why the answer is correct. Note that the explanation involves also explaining why the other answers are not correct.
Your answer Word document should be submitted on the Canvas system for the quiz number equal to the homework number. For example, the homework 2 should be submitted for homework

assignment 2.
1) The Entity-Relationship model is
a) a way to graphically represent the logical relation-ships of entities in a database.
b) a way to graphically represent the data in adatabase.
c) a way to graphically represent only the constraintsin a database.
d) a way to graphically represent strong entity setsbut not weak entity sets.
2) In the Entity-Relationship model, to what does an entity refer (or represent)?
a) The organization in which the model is created.
b) A distinctly identifiable item, thing or object.
c) A particular instance of data.
d) A database schema.
3) An entity set is
a) a collection of databases.
b) a collection of relationships connecting a singleentity to many other entities.
c) a collection of entities of the same type that sharethe same properties.
d) a collection of attribute values that are the sameacross all entities.
4) Entities can be associated with one another by using which of the following?
a) Entities
b) Attributes
c) Identifiers
d) Relationships
5) In a one-to-many relationship, the entity that is on the many side of the relationship is called what type of entity?
a) parent
b) child
c) instance
d) subtype
a) simple
b) composite
c) multi-valued
d) All of the above.
e) None of the above.
7) In an Entity-Relationship model, relationship sets are represented by which of the following?
a) Rectangles
b) Diamonds
c) Lines
d) Ovals
8) Directed lines from a relationship set to all of its related entity sets indicates which type of relationship?
a) One-to-one
b) One-to-many
c) Many-to-one
d) Many-to-many
10) Which of the following is NOT a basic element of the Chen version of the E-R model?
a) Entities
b) Attributes
c) Relationships
d) All of the above.
e) None of the above.
11) An attribute that names or identifies entity instances is a(n):
a) entity
b) attribute
c) identifier
d) relationship
12) In an Entity-Relationship model, double lines connecting
2
an entity set to a relationship set indicates which of the following?
a) Two constraints on the entity set.
b) Every entity participates in up to two relationshipsof the given type.
c) Some entities participate in more than one relation-ship of the given type.
d) Every entity participates in at least one relationshipof the given type.
13) Relationship sets can be used to directly represent which of the following?
a) Entity attributes.
b) Relationships between attribute values.
c) Relationship between multiple entity sets.
d) All of the above.
e) None of the above.
a) The only name within the top of a double sectionedrectangle.
b) Ovals
c) Names above lines
d) The only name within a diamond.
15) In crow’s foot notation of the Entity-Relationship model, consider the simple ER model of entity E1 and entity E2 connected by a relationship line R where the line ends in a crow’s foot at E1 but ends simply as a line at E2. This represents which of the following relationship types?
a) One-to-one
b) Many-to-one
c) One-to-many
d) Many-to-many