Which of the following is true about identifiers of entities?
A) Identifiers must be unique.
B) Identifiers are not normally used in a naming role.
C) The value of an identifier may identify a set of entity instances.
D) Identifiers may not be more than two attributes.
E) An identifier in the E-R model is equivalent to a key in the relational model.
Correct Answer:
Verified
Q4: Recursive relationships can be represented as 1:N
Q5: The E-R Model assumes that all instances
Q6: The subtype symbol is a circle with
Q7: Maximum cardinality indicates whether or not an
Q8: Recursive relationships occur when an entity has
Q10: When an entity class has a relationship
Q11: There is usually only one instance of
Q12: Unified Modeling Language (UML)has quickly replaced the
Q13: In the Entity-Relationship data model,all instances of
Q14: The number of entity classes involved in
Unlock this Answer For Free Now!
View this answer and more for free by performing one of the following actions
Scan the QR code to install the App and get 2 free unlocks
Unlock quizzes for free by uploading documents