Exam 3: Relational Database Modeling

GENERIC ERD Observe the GENERIC ER Diagram below: This ER diagram will be used for the following questions citing Generic ER Diagram. -If in the GENERIC ERD the Symbol 1 is >| and the Symbol2 is ||,then the number of relations in the relational schema resulting from mapping the GENERIC ERD is 2.

Autonumber data type option:

What is the difference between an implicit and user-defined database constraint?

What is a primary key?

ABC RETAILER Observe the ER diagram for the ABC Retailer: This ER diagram will be used for the following questions citing ABC Retailer ER Diagram. -How many columns will the relation PRODUCT have in the relational schema mapped from the ABC Retailer ER diagram?

GENERIC ERD Observe the GENERIC ER Diagram below: This ER diagram will be used for the following questions citing Generic ER Diagram. -If in the GENERIC ERD the Symbol 1 is >| and the Symbol2 is 0|,then the number of optional columns in the relational schema resulting from mapping the GENERIC ERD is 0.

CENTRAL SCHOOL LIBRARY Observe the ER diagram for the CENTRAL SCHOOL LIBRARY -How many tables in the relational schema mapped from the Central School Library ER diagram will have composite primary keys?

GENERIC ERD Observe the GENERIC ER Diagram below: This ER diagram will be used for the following questions citing Generic ER Diagram. -If in the GENERIC ERD the Symbol 1 is >| and the Symbol2 is 0<,then the number of relations in the relational schema resulting from mapping the GENERIC ERD is 2.

What is a business rule?

An entity with two multivalued attributes will be mapped as how many relations?

CENTRAL SCHOOL LIBRARY Observe the ER diagram for the CENTRAL SCHOOL LIBRARY -How many foreign keys in the relational schema mapped from the Central School Library ER diagram serve as a component of a primary key?

CENTRAL SCHOOL LIBRARY Observe the ER diagram for the CENTRAL SCHOOL LIBRARY -What is the minimal number of records that can be entered in the database whose relational schema is mapped from the Central School Library ER diagram?

Every attribute appears only once in an ER diagram

When an entity has multiple unique attributes,each one of them is mapped as a primary key of the resulting relation.

CENTRAL SCHOOL LIBRARY Observe the ER diagram for the CENTRAL SCHOOL LIBRARY -How many columns will the relation AUTHOR have in the relational schema mapped from the Central School Library ER diagram?

If an M:N relationship is optional on both sides,and if both relations resulting from the entities involved in the relationship each have 3 records,then the resulting bridge relation cannot have less than ________ records.

If a 1:M relationship is optional on both sides,and if the table resulting from the 1 side has 3 records,then the table resulting from the M side CANNOT have less than ________ records.

An entity and its 1:1 unary relationship are mapped as one relation.

If an entity has three unique attributes,how many primary keys will its mapped relation have?

Tuple is a synonym for