Chapter 4 Quiz 3 Flashcards
an attribute that must have a value
Required attribute
an attribute that does not require value; therefore, it can be left empty
optional attribute
one or more attributes to uniquely identify each entity instance
identifiers
attributes are also underlined in a frequently used shorthand notation for the table structure called____
Relational schema
a primary key composed of more than one attribute
composite identifier
an attribute that can be further subdivided to yield additional attributes
composite attribute
an attribute that cannot be subdivided
simple attribute
an attribute that can have only a single value
single-valued attribute
attributes that can have any values
multivalued attributes
an attribute whose value is calculated from other attributes
derived attribute
The entities that participate in a relationship are known as______
Participants
_____ is used to describe the relationship classification
connectivity
______expresses the minimum and maximum number of entity occurrences associated with one occurrence of the related entity.
Cardinality
an entity is said to be ______ if it can exist in the database only when it is associated with another related entity occurence
existence-dependent
if an entity can exist apart from all of its related entities, then it is _____ and is referred to as a “_____”
existence-independent, strong entity
a ______ exists if the primary key of the related entity does not contain a primary key component of the parent entity
weak relationship
A______ exists when the primary key of the related entity contains a primary key component of the parent entity
Strong relationship
a _____ exists when thee entity is existence-dependent and the entity has a primary key that is derived from the parent entity in the relationship
Weak entity
_______ means that one entity occurrence does not require a corresponding entity occurrence
Optional participation
______ means that one entity occurrence requires a corresponding entity occurrence in a particular relationship
Mandatory participation
_____ indicated the number of entities or participants associated with a relationship
Relationship degree
____ exists when an association is maintained within a single entity
unary relationship
A ____ exists when two entities are associated
binary relationship
A____ exists when three entities are associated
ternary relationship
when a relationship is related to itself
recursive relationship
an_____ is based on repetition of processes and procedures
Iterative process
