Q&A Hero

Humanities

Q: Suppose you have created a data model for an airline based on a variety of forms, reports, user interviews, data sources, etc. Your client comes forward with a new desired report that includes passenger weights and a relationship between passengers and employees, neither of which is in your E-R diagram. You should ________. A) create a new, separate E-R diagram with just the new information B) add the relationship and the weight attribute to the existing data model C) add the relationship but not the weight attribute D) add the weight attribute but not the relationship
Q: Recursive relationships can have all of the following maximum cardinalities except ________. A) 1:1 B) 1:N C) N:M D) M:M
Q: When an entity has a relationship to itself, we have a(n) ________. A) supertype/subtype relationship B) archetype/instance relationship C) recursive relationship D) Both A and C are correct
Q: A for-use-by pattern must involve what kind of entity? A) Strong entity B) Supertype entity C) Weak entity with one identifying relationship D) Weak entity with two identifying relationships
Q: A line-item pattern must involve what kind of entity? A) Strong entity B) Supertype entity C) Weak entity with one identifying relationship D) Weak entity with two identifying relationships
Q: To represent an archetype/instance pattern in an E-R model, ________. A) create a new ID-dependent entity with a 1:N relationship B) create a new weak, but not ID-dependent entity with a 1:N relationship C) create a new strong entity with a 1:1 relationship D) create a new ID-dependent entity with a 1:1 relationship
Q: To represent a multivalued attribute in an E-R model, ________. A) create a new ID-dependent entity with a 1:N relationship B) create a new weak, but not ID-dependent entity with a 1:N relationship C) create a new strong entity with a 1:1 relationship D) create a new ID-dependent entity with a 1:1 relationship
Q: To represent an association pattern in an E-R model, ________. A) create a new ID-dependent entity with a 1:1 relationship to one other entity B) create a new weak, but not ID-dependent entity with a 1:1 relationship to one other entity C) create a new strong entity with a 1:1 relationship to one other entity D) create a new ID-dependent entity with a N:1 relationships to two parent entities
Q: Supertype/subtype entities are said to have a(n) ________ relationship. A) HAS-A B) IS-A C) recursive D) redundant
Q: Discriminators can be ________. A) attributes B) entities C) relationships D) subtypes
Q: An attribute that determines which subtype should be used is a(n) ________. A) supertype B) subtype C) discriminator D) identifier
Q: Which of the following is not true about subtype entities? A) Subtypes may be exclusive. B) The supertype and subtypes will have the same identifier. C) Subtypes are used to avoid a situation in which some attributes are required to be null. D) All subtypes of a supertype must have the same attributes.
Q: An entity that holds specialized attributes that distinguish it from one or more other similar entities is a ________. A) supertype B) subtype C) discriminator D) parent
Q: Which of the following is considered to be a weak entity? A) A subtype entity B) The archetype in an archetype/instance pattern C) The association entity in an association pattern D) The parent entity in a parent-child relationship
Q: An entity whose existence depends on the presence of another entity but whose identifier does not include the identifier of the other entity is a(n) ________. A) strong entity B) weak entity C) ID-dependent entity D) subtype entity
Q: An entity whose identifier includes the identifier of another entity is a(n) ________. A) strong entity B) weak entity C) optional entity D) required entity
Q: You are given an E-R diagram with two entities, ORDER and CUSTOMER, as shown above. What does the symbol next to the CUSTOMER entity indicate? A) A maximum cardinality of "zero" B) A maximum cardinality of "one" C) A minimum cardinality of "optional" D) A minimum cardinality of "required"
Q: You are given an E-R diagram with two entities, ORDER and CUSTOMER, as shown above. What does the symbol next to the ORDER entity indicate?A) A maximum cardinality of "zero"B) A maximum cardinality of "one"C) A minimum cardinality of "optional"D) A minimum cardinality of "required"
Q: A circle across the relationship line near an entity indicates ________.A) a maximum cardinality of "zero"B) a maximum cardinality of "one"C) a minimum cardinality of "optional"D) a minimum cardinality of "required"
Q: A hash mark across the relationship line near an entity indicates ________. A) a maximum cardinality of "zero" B) a maximum cardinality of "one" C) a minimum cardinality of "optional" D) a minimum cardinality of "required"
Q: In a minimum cardinality, minimums are generally stated as ________. A) 0 or 1 B) 1 or N C) M or N D) one or many
Q: Minimum cardinality refers to ________. A) the most instances of one entity class that can be involved in a relationship with one instance of another entity class B) the minimum number of entity classes involved in a relationship C) whether or not an instance of one entity class is required to be related to an instance of another entity class D) whether or not an entity is a weak entity
Q: You are given an E-R diagram with two entities, ORDER and CUSTOMER, as shown above, and are asked to draw the relationship between them. If a given customer can place many orders and a given order can be placed by one or more customers, which of the following should be indicated in the relationship symbol between the two entities? A) N:M B) 1:1 C) 1:N D) N:1
Q: You are given an E-R diagram with two entities, ORDER and CUSTOMER, as shown above, and are asked to draw the relationship between them. If a given customer can place many orders and a given order can be placed by at most one customer, which of the following should be indicated in the relationship symbol between the two entities? A) N:M B) 1:1 C) 1:N D) N:1
Q: You are given an E-R diagram with two entities, ORDER and CUSTOMER, as shown above, and are asked to draw the relationship between them. If a given customer can place only one order and a given order can be placed by at most one customer, which of the following should be indicated in the relationship symbol between the two entities?A) N:MB) 1:1C) 1:ND) N:1
Q: Maximum cardinality refers to ________.A) the most instances of one entity class that can be involved in a relationship instance with another entity classB) the minimum number of entity classes involved in a relationshipC) whether or not an instance of one entity class is required to be related to an instance of another entity classD) whether or not an entity is a weak entity
Q: Which of the following is not a common variant of the E-R model? A) IE Crow's Foot B) IDEF1X C) UML D) Object-oriented
Q: For a relationship to be considered a binary relationship it must satisfy which of the following conditions? A) It must involve exactly two entity classes. B) It must have a maximum cardinality of 1:1. C) It must have a maximum cardinality of 1:N. D) Both A and B are correct
Q: A composite attribute is an attribute that ________. A) is multivalued B) describes a characteristic of the relationship C) consists of a group of attributes D) is calculated at run-time
Q: An identifier may be ________. A) composite B) optional C) a relationship D) minimal
Q: Attributes may be ________. A) complete B) optional C) multivalued D) required
Q: The characteristics of a thing are described by its ________. A) identifiers B) entities C) objects D) attributes
Q: An occurrence of a particular entity is called an ________. A) entity class B) entity relationship C) entity instance D) entity attribute
Q: Entities of a given type are grouped into an ________. A) entity class B) entity relationship C) entity instance D) entity attribute
Q: Which of the following is not a key element of an E-R model? A) Relationships B) Entities C) Objects D) Attributes
Q: Which of the following is not a good reason for designing a data model? A) It's easier to change things in the data model than it is in the actual DBMS. B) The data model provides a simplified view of the database that can be shown to people who don't need to see all the details. C) Creating a data model will help you understand the application area better. D) The data model can be discarded after the database is operational.
Q: Recursive relationships only exist for one-to-one relationships.
Q: There are three types of recursive relationships: 1:1, 1:N, and N:M.
Q: Relationships among instances of a single entity class are called redundant relationships.
Q: Relationships between supertypes and subtypes are called IS-A relationships.
Q: Subtypes can be exclusive or inclusive.
Q: The supremetype entity contains the attributes that are common to all subtypes.
Q: Entities containing multivalued attributes are often represented using subtypes.
Q: Data modelers agree that weak, non-ID-dependent entities exist and are important.
Q: One example of a database design using an ID-dependent relationship is the archetype/instance pattern.
Q: One example of a database design using a strong relationship is the multivalued attribute pattern.
Q: One example of a database design using an ID-dependent relationship is the association pattern.
Q: Entities with an IS-A relationship should have the same identifier.
Q: An exclusive subtype pattern has one supertype entity that relates to one or more subtype entities.
Q: An attribute that determines which subtype is appropriate is called a discriminator.
Q: Subtype entities contain, apart from the identifier, only attributes that do not appear in the supertype.
Q: All weak entities must have a minimum cardinality of 1 on the entity on which it depends.
Q: ID-dependent entities are a common type of weak entity.
Q: A weak entity is an entity that cannot exist in the database without (and is logically dependent upon) another type of entity also existing in the database.
Q: ID-dependent entities are associated by a nonidentifying relationship.
Q: An ID-dependent entity is an entity whose identifier includes the identifier of another entity.
Q: E-R models use an identifying relationship to connect entities that are ID-dependent.
Q: An entity that represents something that can exist on its own is called a strong entity.
Q: In an E-R model, the three types of minimum cardinality are mandatory, optional, and indeterminate.
Q: An entity's minimum cardinality in a relationship indicates whether or not an entity must participate in the relationship.
Q: An entity's minimum cardinality in a relationship indicates the number of entity instances that must participate in the relationship.
Q: In a 1:N relationship, the parent entity is on the one side of the relationship, and the child entity is on the many side of the relationship.
Q: In a 1:N relationship, the term parent refers to the N side of the relationship.
Q: In an E-R model, the three types of maximum cardinality are 1:1, 1:N, and N:M.
Q: A relationship's maximum cardinality indicates the maximum number of entities that can participate in the relationship.
Q: Relationships are classified by their cardinality.
Q: The notation 1:N shows a relationship's maximum cardinalities.
Q: When designing a database, first identify the entities, then determine the attributes, and finally create the relationships.
Q: The principal difference between an entity and a table is that you can express a relationship between entities without using foreign keys.
Q: When transforming a data model into a relational design, relationships of all degrees are treated as combinations of binary relationships.
Q: The degree of a relationship is expressed as the relationship's maximum cardinality.
Q: A binary relationship is a relationship based on numerical entity instance identifiers.
Q: A single relationship class involves only one entity class.
Q: In today's E-R models, attributes of relationships are still used.
Q: E-R modeling recognizes both relationship classes and relationship instances.
Q: Relationships of degree two are referred to as binary relationships.
Q: A binary relationship is a relationship between two or more entities.
Q: The degree of a relationship is the number of entity classes in the relationship.
Q: Entities can be associated with one another in relationships.
Q: An identifier serves the same role for a table that a key does for an entity.
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