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, a supervisor cannot supervise more than one employee. incorrect According to the model, an employee can work in multiple departments. incorrect According to the model, an employee should always work on projects assigned to his/her department. incorrect According to the model, an employee can manage multiple departments. correct
MC Consider a data model for the Olympics storing information about countries and athletes. There is a 1-N relationship type between country and athlete and an athlete always has to belong to exactly 1 country. A relational data model containing only 1 table leads to: Unnecessary replication of data about athletes. incorrect No unnecessary replication of data. incorrect Unnecessary replication of data about athletes and countries. incorrect Unnecessary replication of data about countries. correct
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 can manage multiple departments. correct According to the model, an employee should always work on projects assigned to his/her department. incorrect According to the model, an employee can work in multiple departments. incorrect According to the model, a supervisor cannot supervise more than one employee. incorrect
MC Consider the following EER model
Which statement is CORRECT? When mapping the EER relationship type INVOLVE between COURSE and ASSIGNMENT to the relational model, a new relation needs to be introduced. The 1..1 cardinalities of this relationship type cannot be enforced in the relational model. incorrect When mapping the EER relationship type PARTICIPATE between GROUP ASSIGNMENT and STUDENT to the relational model, a new relation needs to be introduced. The 4 cardinalities of this EER relationship type can be perfectly mapped to the relational model. incorrect When mapping the EER relationship type IS_ENROLLED between COURSE and STUDENT to the relational model, a new relation needs to be introduced. The relation is identified by GRADE as its primary key. incorrect The partial inheritance relationship between STUDENT and REPRESENTATIVE can be perfectly mapped to the relational model by the following two relations: STUDENT(StudentID, FirstName, LastName) and REPRESENTATIVE (S-StudentID, Email) whereby S-StudentID refers to StudentID in STUDENT. correct
MC Consider a data model for the Olympics storing information about countries and athletes. There is a 1-N relationship type between country and athlete and an athlete always has to belong to exactly 1 country. A relational data model containing only 1 table leads to: No unnecessary replication of data. incorrect Unnecessary replication of data about countries. correct Unnecessary replication of data about athletes. incorrect Unnecessary replication of data about athletes and countries. 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 can work in multiple departments. incorrect 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
MC Which statement is NOT CORRECT? The Boyce Codd normal form is more strict than the third normal form. incorrect A foreign key can be NULL. incorrect A relation is in 3NF if it is in BCNF and no prime attribute type of R is transitively dependent on the primary key. correct In mapping an EER N:M relationship type to the relational model, we create a new relation R. Its primary key is the combination of the foreign keys referring to the primary keys of the relations corresponding to the participating entity types. incorrect
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 non-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 nonprime attribute type of R is transitively dependent on the primary key. correct
MC Consider a data model for the Olympics storing information about countries and athletes. There is a 1-N relationship type between country and athlete and an athlete always has to belong to exactly 1 country. A relational data model containing only 1 table leads to: Unnecessary replication of data about countries. correct Unnecessary replication of data about athletes. incorrect No unnecessary replication of data. incorrect Unnecessary replication of data about athletes and countries. incorrect
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 course to be followed by multiple students. incorrect 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