Worksheet Questions

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

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) Author, Title → Publisher

A table that displays data redundancies yields the following anomalies:

(a) Update anomalies (b) Insertion anomalies (c) Deletion anomalies

If {A, B} → {C, D} is one functional dependency that holds for relation schema R(A,B,C,D), then

-{A, B} is a candidate key for R -No two tuples in R can have the same values for both A and B -{A, B} is a primary key for R

Superclass

A class that has been specialized into subclasses and/or the generalized class that has been formed from a group of related subclasses

The functional dependency {A} → {B} for relation schema R(A,B,C,D) implies that

Any two tuples in R that have the same value for A must have the same value for B

A table where every determinant is a candidate key is said to be in

BCNF

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

FALSE

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

FALSE

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

FALSE

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

Lossless

A relation schema R is in 3rd Normal Form if

R satisfies 2nd Normal Form and no nonprime attribute of R is transitively dependent on the primary key

A BCNF relation is always in 3rd Normal Form

TRUE

A Prime attribute must be a member of some candidate key

TRUE

A binary relation is in BCNF

TRUE

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

TRUE

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

TRUE

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

TRUE

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

TRUE

If a relation R is decomposed into {R1, R2, ..., Rn} and the decomposition is lossless then

The natural join of R1, R2,..., Rn will have the same number of tuples as the original relation R

Specific attributes

attributes local to a particular subclass

IS-A relationship

implicit relationship between a super class and its subclass

Inheritance

the act of a subclass including all attributes and relationships of its superclass

Specialization

the act of refining an entity into subdivided entities, identifying specific attributes and specific relationship types

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, B} is a key for R