Database Final

A tuple is: a. An ordered set of attributes b. Ordered within a relation c. All of the possible values of an attribute d. The same thing as a "table"

A

The unary relational operations are a. SELECT PROJECT RENAME b. UNION INTERSECTION DIFFERENCE C. SELECT PROJECT REJECT d. UNION CONFEDERACY DUNCES

A

Produces a relation that has all of the attributes and all of the tuples in all possible combinations of two relations event if they are not union compatible.

Cartesian Product

A natural join a. Uses a * notation b. Combines all attributions of both relations c. Joins attributes with the same name d. All of the above

D

A table that displays data redundancies yields the following anomalies: (a) Update anomalies (b) Insertion anomalies (c) Deletion anomalies (d) All of the above (e) None of the above

D

Binary 1:1 relationships are mapped to a relational model by: a. Composite attributes common to both entities b. Combination of all candidate keys c. A surrogate key named the same as the relationship it represents d. A foreign key on the entity that fully participates in the relationship

D

Which of the following is true about disjoint subclasses: a. An entity can be a member of at most one of the subclasses of the specialization b. A superclass can have partial participation in disjoint subclasses c. A superclass can have total participation in disjoint subclasses d. All of the above e. None of the above

D

Produces a relation that includes all of the tuples in one relation, that are not also in another relation, if they are union compatible.

Difference

Produces all of the combinations of tuples from two relations that satisfy only equality conditions

Equijoin

A relation schema R is in Second Normal Form (2NF) if every non-prime attribute A in R is functionally dependent (FD) on the primary key

F

A relation schema R is in generalized Third Normal Form (3NF) if when a FD X → A holds in R, then X is a superkey of R and A is a prime attribute of R

F

Produces all the combinations of tuples from two relations that satisfy only equality conditions, but if two attributes have the same name they do not have to be specified.

Natural Join

Selects all tuples that satisfy the selection condition from a relation

Select

A BCNF relation is always in 3rd Normal Form

T

A Prime attribute must be a member of some candidate key

T

A binary relation is in BCNF

T

A relation where all attributes are atomic is always in 1st Normal Form

T

Football PLAYER entities are specialized into QUARTERBACK , RUNNING BACK and WIDE RECEIVER subclasses. What can be said of the subclasses entities: a. They must have all of the attributes of PLAYER and must participate in all of the relationships of the PLAYER b. They may have some of the attributes of PLAYER and may participate in some of the relationships of the PLAYER c. They must have all of the attributes of PLAYER and may not participate in any of the relationships of the PLAYER d. None of the above

A

Given only the relation schema Books (Title, Author, Year, Publisher), we can infer the following functional dependency: (a) Author, Title → Publisher (b) Title → Author (c) Year → Publisher (d) Author → Publisher

A

Weak entities: a. Are related to specific entities by identifying relationships b. Have partial keys to uniquely identify them c. Have a partial participation constraint d. Are required in ER diagrams

A

What does this expression mean? Dno F average(salary)(Employee) a. Average salary by department b. Average salary of all employees c. Average salary of all departments d. Employee salary compared to the dept. average

A

When mapping a regular entity to a relational model which of the following apply: a. Every simple attribute maps to an attribute of the relation b. Every multi-value attribute maps to an attribute of the relation c. Every derived attributes maps to an attributes of the relation d. All of the above e. None of the above

A

A primary key of a weak entity is composed of: a. Primary key of the identifying entity as a foreign key b. Both primary key of the identifying entity as a foreign key and the partial key c. Partial key d. Partial key of the identifying entity as a foreign key

B

Compared to a INTERSECTION, a RIGHT OUTER JOIN may a. Include less tuples b. Include more tuples c. Include only the same tuples d. Include the opposite set of tuples

B

If the following functional dependencies, ({A} → {B}, {B} → {C}) hold for database schema R(A,B) and S(B,C), then the join of R and S will be (a) Lossy (b) Lossless (c) Non lossless (d) None of the above

B

In a retail store, a database tracks all purchases made. On a purchase order there are items, prices, and quantities. The name of one of the items is an example of: a. A relationship b. An attribute c. An entity d. A superclass

B

Updating a student's Telephone Number to 'LP0XI-28-ZXD46' represents what kind of violation: a. Key constraint b. Domain constraint c. Entity constraint d. Relational Integrity constraint

B

Which best describes this relationship: Customer----(0,N)----Orders----(1,1)-----Drink a. A customer must order one drink b. A customer may order many drinks c. A drink may be ordered by many customers d. A drink orders one and only one customer

B

A relation schema R is in 3rd Normal Form if (a) Each nonprime attribute in R is fully dependent on every key (b) All attributes in R have atomic domains (c) R satisfies 2nd Normal Form and no nonprime attribute of R is transitively dependent on the primary key (d) R contains only 3 keys

C

An example of Cardinality is: a. Disjoint b. Overlapping c. 1-to-many d. Partial

C

Given the set of functional dependencies, ({A, B} → {C, D, E} and {A} → {E}), for relation schema R = (A,B,C,D,E) we can infer the following: (a) {A} is a key for R (b) {B, E} is a key for R (c) {A, B} is a key for R (d) None of the above

C

If a relation R is decomposed into {R1, R2, ..., Rn} and the decomposition is lossless then (a) The natural join of R1, R2, ..., Rn can have more tuples than the original relation for R (b) The relations R1, R2, ...,Rn are each in 3rd Normal Form (c) The natural join of R1, R2,..., Rn will have the same number of tuples as the original relation R (d) None of the above

C

Inserting a NULL for the primary key of a tuple represents what kind of violation: a. Key constraint b. Domain constraint c. Entity constraint d. Relational Integrity constraint

C

Ternary relationships: a. Are equivalent to three binary relationships b. Are widely supported by most databases c. Can adequately be represented as a separate relation with an artificial key d. Must have identifying attributes

C

When selecting from a table, which of the following is true about he SQL select? a. WHERE and FROM are both required clauses b. WHERE and FROM are both optional c. WHERE is optional, but FROM is required d. WHERE is required but FROM is optional

C

Which statement can select all of the attributes and all of the tuples from relation R? a. SELECT FROM R b. SELECT R* c. SELECT * FROM R d. all of the above

C

All of these are types of attributes, except: a. Composite b. Multi-valued c. Atomic d. Disjoint e. All of the above

D

If {A, B} → {C, D} is one functional dependency that holds for relation schema R(A,B,C,D), then (a) {A, B} is a candidate key for R (b) No two tuples in R can have the same values for both A and B (c) {A, B} is a primary key for R (d) All of the above

D

The functional dependency {A} → {B} for relation schema R(A,B,C,D) implies that (a) No two tuples in R can have the same value for attribute B (b) Any two tuples in R that have the same value for B must have the same value for A (c) No two tuples in R can have the same value for attribute A (d) Any two tuples in R that have the same value for A must have the same value for B

D

The relational algebra expression R-S includes all tuples in a. Either R or S or both b. In both R and S c. R and unmatched tuples in S d. R but not in S

D

The term First Normal Form (1NF) describes the tabular format in which: (a) All the key attributes are defined (b) There are no repeating groups in the table. Row/column intersection can contain one and only one value, not a set of values (c) All attributes are dependent on the primary key (d) All of the above (e) None of the above

D

Using the relational diagrams below, suppose that S1 is a foreign key referring to A1. Which of the following statements must be true: a. Values for A1 must correspond to existing values for S1 b. Values for S1 may not be NULL c. S1 should have the same name as A1 d. Values for S1 must be the same type and in the same domain as A1

D

What are the benefits of using the Three Scheme Architecture? a. Change the physical disk storage without changing conceptual schema b. Gives different users different views of the same data c. Data Independence d. All of the above e. None of the above

D

What can be said about a Key: a. Is a superkey b. Can have more than one in a tuple c. Uniquely identifies a tuple d. All of the above e. None of the above

D

Which best describes this relationship: Player ---1---Scores ---N---Touchdown a. A touchdown is scored by many players b. A player must score many touchdowns c. A touchdown may be scored by a player d. A player can score many touchdowns

D

A table where every determinant is a candidate key is said to be in (a) 4NF (b) 3NF (c) 2NF (d) 1NF (e) BCNF

E

Full functional dependency means a FD Y → Z where removal of any attribute from Z means the FD does not hold any more

F

Produces a relation that includes all of the tuples that are in both of two relations, if they are union compatible.

Intersection

Produces a relation with all of the tuples of one relation, and also the matching tuples of another relation.

Outer Join

Produces a new relation with only some of the attributes

Project

What does this query do? SELECT S.Name, S.Major FROM STUDENT S WHERE NOT EXISTS (SELECT * FROM GRADE_REPORT G WHERE G.StudentNumber=S.StudentNumber AND G.Grade='E')

Retrieve the names and majors of all students who do not have a grade of E in other courses

A relation schema R is in Third Normal Form (3NF) if it is in 2NF and no non-prime attribute in R is transitively dependent on the primary key

T

Transitive functional dependency means a FD X → Z that can be derived from two FDs X → Y and Y → Z

T

X → Y holds if whenever two tuples have the same value for X, they must have the same value for Y

T

Produces all combinations of tuples from two relations that satisfy the join condition

Theta Join

Produces a relation that includes all of the tuples in two relations, if they are union compatible.

Union