Composite identifiers consist of two or more attributes.
Composite identifiers consist of two or more attributes.
Entities use identifiers while tables use keys.
Entities use identifiers while tables use keys.
Which type of entity cannot exist in the database unless another type of entity also exists in the database, but does not require that the identifier of that other entity be included as part of its own identifier?
Which type of entity cannot exist in the database unless another type of entity also exists in the database, but does not require that the identifier of that other entity be included as part of its own identifier?
An entity class is a collection of entities and is described by the structure of the entities in that class.
An entity class is a collection of entities and is described by the structure of the entities in that class.
Properties that describe the characteristics of entities are called:
Properties that describe the characteristics of entities are called:
In a 1:N relationship, the parent is the entity on the one side of the relationship and the child is the entity on the N side of the relationship.
In a 1:N relationship, the parent is the entity on the one side of the relationship and the child is the entity on the N side of the relationship.
Which of the following indicates the maximum number of entities that can be involved in a relationship?
Which of the following indicates the maximum number of entities that can be involved in a relationship?
A ternary relationship is so called because in contains two entities and one association between them.
A ternary relationship is so called because in contains two entities and one association between them.
A recursive relationship is a relationship between an entity and ________ .
A recursive relationship is a relationship between an entity and ________ .
In which of the following is a single-entity instance of one type of related to a single-entity instance of another type?
In which of the following is a single-entity instance of one type of related to a single-entity instance of another type?
An attribute describes the entity's characteristics.
An attribute describes the entity's characteristics.
Which of the following is NOT a basic element of all versions of the E-R model?
Which of the following is NOT a basic element of all versions of the E-R model?
An attribute that names or identifies entity instances is a(n):
An attribute that names or identifies entity instances is a(n):
In a one-to-many relationship, the entity that is on the many side of the relationship is called a(n) ________ entity.
In a one-to-many relationship, the entity that is on the many side of the relationship is called a(n) ________ entity.
Entities can be associated with one another in which of the following?
Entities can be associated with one another in which of the following?
An ID-dependent entity is an entity whose identifier is a composite identifier where no portion of the composite identifier is an identifier of another entity.
An ID-dependent entity is an entity whose identifier is a composite identifier where no portion of the composite identifier is an identifier of another entity.
In a one-to-many relationship, the entity that is on the one side of the relationship is called a(n) ________ entity.
In a one-to-many relationship, the entity that is on the one side of the relationship is called a(n) ________ entity.
A recursive relationship is a relationship between an archetype and an instance of that archetype.
A recursive relationship is a relationship between an archetype and an instance of that archetype.
A minimum cardinality is the minimum number of entity instances that may participate in a relationship instance.
A minimum cardinality is the minimum number of entity instances that may participate in a relationship instance.
Which type of entity represents an actual occurrence of an associated generalized entity?
Which type of entity represents an actual occurrence of an associated generalized entity?
Which of the following refers to something that can be identified in the user's work environment, something that the users want to track?
Which of the following refers to something that can be identified in the user's work environment, something that the users want to track?
Which type of entity is related to two or more associated entities that each contain specialized attributes that apply to some but not all of the instances of the entity?
Which type of entity is related to two or more associated entities that each contain specialized attributes that apply to some but not all of the instances of the entity?
Relationship classes are associations between entity classes.
Relationship classes are associations between entity classes.
An identifier determines the type of relationship that an entity has.
An identifier determines the type of relationship that an entity has.
Which type of entity has its relationship to another entity determined by an attribute in that other entity called a discriminator?
Which type of entity has its relationship to another entity determined by an attribute in that other entity called a discriminator?
Which of the following indicates the minimum number of entities that must be involved in a relationship?
Which of the following indicates the minimum number of entities that must be involved in a relationship?
When designing a database, first identify the entities, then determine the attributes, and finally establish the relationships.
When designing a database, first identify the entities, then determine the attributes, and finally establish the relationships.
1:1, 1:N and N:M relationships are also known as HAS-A relationships.
1:1, 1:N and N:M relationships are also known as HAS-A relationships.
Entities of a given type are grouped into a(n):
Entities of a given type are grouped into a(n):
The degree of a relationship refers to the number of entity classes in the relationship.
The degree of a relationship refers to the number of entity classes in the relationship.
A subtype entity is a special case of another entity called a supertype entity.
A subtype entity is a special case of another entity called a supertype entity.
An entity is something that can be identified in the user's work environment; something that the users want to track.
An entity is something that can be identified in the user's work environment; something that the users want to track.
Entity instances are associated by relationship classes.
Entity instances are associated by relationship classes.
Which of the following refers to an entity in which the identifier of one entity includes the identifier of another entity?
Which of the following refers to an entity in which the identifier of one entity includes the identifier of another entity?
In which of the following can many entity instances of one type be related to many entity instances of another type?
In which of the following can many entity instances of one type be related to many entity instances of another type?
All instances of an entity class have the same attributes.
All instances of an entity class have the same attributes.
Which type of entity represents a logical generalization whose actual occurrence is represented by a second, associated entity?
Which type of entity represents a logical generalization whose actual occurrence is represented by a second, associated entity?
An identifier typically uses more than one attribute.
An identifier typically uses more than one attribute.
In which of the following is a single-entity instance of one type related to many entity instances of another type?
In which of the following is a single-entity instance of one type related to many entity instances of another type?
A maximum cardinality is the maximum number of entity instances that can participate in a relationship instance.
A maximum cardinality is the maximum number of entity instances that can participate in a relationship instance.
