WGU C170 Chapter 2.|Latest Update
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binary relationship
An ER term for an association (relationship) between two entities. For example, PROFESSOR teaches
CLASS.
cardinality
An attribute that can be further subdivided to yield additional attributes. For example, a phone
number such as 615-898-2368 may be divided into an area code (615), an exchange number (898),
and a four-digit code (2368). Compare to simple attribute.
composite identifier
In ER modeling, a key composed of more than one attribute.
derived attribute
An attribute that does not physically exist within the entity and is derived via an algorithm. For
example, the Age attribute might be derived by subtracting the birth date from the current date.
existence-dependent
A property of an entity whose existence depends on one or more other entities. In such an
environment, the existence-independent table must be created and loaded first because the
existence-dependent key cannot reference a table that does not yet exist.
existence-independent
A property of an entity that can exist apart from one or more related entities. Such a table must be
created first when referencing an existence-dependent table.
identifiers
One or more attributes that uniquely identify each entity instance.
iterative process
A process based on repetition of steps and procedures.
mandatory participation
A relationship in which one entity occurrence must have a corresponding occurrence in another
entity. For example, an EMPLOYEE works in a DIVISION. (A person cannot be an employee without
being assigned to a company's division.)
multivalued attributes
An attribute that can have many values for a single entity occurrence. For example, an EMP_DEGREE
attribute might store the string "BBA, MBA, PHD" to indicate three different degrees held.
non-identifying relationship
A relationship in which the primary key of the related entity does not contain a primary key
component of the parent entity.
Complete with A+ Graded Answers
binary relationship
An ER term for an association (relationship) between two entities. For example, PROFESSOR teaches
CLASS.
cardinality
An attribute that can be further subdivided to yield additional attributes. For example, a phone
number such as 615-898-2368 may be divided into an area code (615), an exchange number (898),
and a four-digit code (2368). Compare to simple attribute.
composite identifier
In ER modeling, a key composed of more than one attribute.
derived attribute
An attribute that does not physically exist within the entity and is derived via an algorithm. For
example, the Age attribute might be derived by subtracting the birth date from the current date.
existence-dependent
A property of an entity whose existence depends on one or more other entities. In such an
environment, the existence-independent table must be created and loaded first because the
existence-dependent key cannot reference a table that does not yet exist.
existence-independent
A property of an entity that can exist apart from one or more related entities. Such a table must be
created first when referencing an existence-dependent table.
identifiers
One or more attributes that uniquely identify each entity instance.
iterative process
A process based on repetition of steps and procedures.
mandatory participation
A relationship in which one entity occurrence must have a corresponding occurrence in another
entity. For example, an EMPLOYEE works in a DIVISION. (A person cannot be an employee without
being assigned to a company's division.)
multivalued attributes
An attribute that can have many values for a single entity occurrence. For example, an EMP_DEGREE
attribute might store the string "BBA, MBA, PHD" to indicate three different degrees held.
non-identifying relationship
A relationship in which the primary key of the related entity does not contain a primary key
component of the parent entity.
