MC A relation is in 3 NF if it satisfies 2 NF and... no primary key of R is transitively dependent on a prime attribute type. incorrect no prime attribute type of R is transitively dependent on the primary key. incorrect no non-primary key of R is transitively dependent on a prime attribute type. incorrect no nonprime attribute type of R is transitively dependent on the primary key. correct
MC Which statement is CORRECT? A foreign key of a relation A cannot refer to the primary key of the same relation A. incorrect Every relation must have a foreign key. incorrect A relation cannot have more than 1 foreign key. incorrect A foreign key can be NULL. correct
MC Given the following relational model (primary keys are underlined, foreign keys in italics):
STUDENT(studentnumber, studentname, street name, street number, zip code, city)
ENROLLED(student_number, course_number)
COURSE(course number, course name)
PROFESSOR(professor number, professor name)
TEACHES(course number, professor number)
Which statement is CORRECT? The model can be further normalized. correct The model does not allow a professor to teach multiple courses. incorrect The model does not allow a course to be taught by multiple professors. incorrect The model does not allow a course to be followed by multiple students. incorrect
MC Given the following (normalized) relational model (primary keys are underlined, foreign keys are in italics).
EMPLOYEE(SSN, ENAME, EADDRESS, SEX, DATE_OF_BIRTH, SUPERVISOR, DNR)
SUPERVISOR: foreign key, refers to SSN in EMPLOYEE, NULL value allowed
DNR: foreign key, refers to DNR in DEPARTMENT, NULL value not allowed
DEPARTMENT(DNR, DNAME, DLOCATION, MGNR)
MGNR: foreign key, refers to SSN in EMPLOYEE, NULL value not allowed
PROJECT(PNR, PNAME, PDURATION, DNR)
DNR: foreign key, refers to DNR in DEPARTMENT, NULL value not allowed)
WORKS_ON(SSN, PNR,, HOURS)
SSN: foreign key, refers to SSN in EMPLOYEE, NULL value not allowed
PNR: foreign key, refers to PNR in PROJECT, NULL value not allowed
Which statement is CORRECT? According to the model, an employee should always work on projects assigned to his/her department. incorrect According to the model, a supervisor cannot supervise more than one employee. incorrect According to the model, an employee can manage multiple departments. correct According to the model, an employee can work in multiple departments. incorrect
MC The following relational model represents a HRM system of a consultancy firm. The primary keys are underlined while foreign keys are in italic font.
Consultant (ConsultantID, Date of Birth, Expertise)
Assigned_to (ConsultantID, ProjectID)
ConsultantID refers to ConsultantID in Consultant
ProjectID refers to ProjectID in Project
Project (ProjectID, Description, Type, Company)
Company refers to Name in Company
Company (Name, Location)
Suppose a new consultant is hired and immediately assigned to a new training project at a new firm and to 2 other, already existing projects. How many rows (tuples) must be added to the database to reflect this change? 5 incorrect 1 incorrect 6 correct 3 incorrect
MC Given the following (normalized) relational model (primary keys underlined; foreign keys in italics):
EMPLOYEE(SSN, ENAME, EADDRESS, SEX, DATE_OF_BIRTH, SUPERVISOR, DNR)
SUPERVISOR: foreign key, refers to SSN in EMPLOYEE, NULL value not allowed
DNR: foreign key, refers to DNR in DEPARTMENT, NULL value not allowed
DEPARTMENT(DNR, DNAME, DLOCATION, MGNR)
MGNR: foreign key, refers to SSN in EMPLOYEE, NULL value not allowed
PROJECT(PNR, PNAME, PDURATION, DNR)
DNR: foreign key, refers to DNR in DEPARTMENT, NULL value not allowed
WORKS_ON(SSN, PNR, HOURS)
SSN: foreign key, refers to SSN in EMPLOYEE, NULL value not allowed
PNR: foreign key, refers to PNR in PROJECT, NULL value not allowed
Which statement is NOT CORRECT? A department has always exactly one manager. incorrect Every project is always assigned to exactly one department. incorrect An employee must work in the same department than he/she manages. correct Every employee must be always supervised by exactly one other employee. incorrect
MC Given the following relational model (primary keys are underlined, foreign keys are in italics)
BOOK(ISBN, title, pages, price, publishername)
AUTHOR(authorname, date_of_birth)
WRITES(authorname, ISBN)
PUBLISHER(publishername, streetnumber, streetname, zipcode)
CITY(zipcode, city)
The assumptions are: