Database Processing, 15e (Kroenke)
Chapter 3: The Relational Model and Normalization
1) All relations are tables, but not all tables are relations.
2) A relation is a table that has special restrictions on it.
3) A characteristic of a relation is that the cells of the relation hold a single value.
4) A characteristic of a relation is that the rows of a relation may hold identical values.
5) A relation is a table composed of columns and rows.
6) In relational terms as defined by E.F. Codd, a row is called a tuple.
7) In relational terms as defined by E.F. Codd, a column is called an attribute.
8) The columns of a relation are sometimes called tuples.
9) A tuple is a group of one or more columns that uniquely identifies a row.
10) A functional dependency is a relationship between attributes such that if we know the value
of one attribute, we can determine the value of the other attribute.
11) If by knowing the value of A we can find the value of B, then we would say that B is
functionally dependent on A.
12) In functional dependencies, the attribute whose value is known or given is referred to as the
determinant.
13) Attribute Y is functionally dependent on attribute X if the value of attribute X determines the
value of Y.
14) The functional dependency noted as A → B means that the value of A can be determined
from the value of B.
15) In the functional dependency shown as A → B, B is the determinant.
16) Functional dependencies can involve groups of attributes.
17) Given the functional dependency (A, B) → C, the attributes (A, B) are referred to as a
composite determinant.
18) Given the functional dependency A → (B, C), then it is true that A → B and A → C.
19) Given the functional dependency (A, B) → C, then it is true that A → C and B → C.
20) Given the functional dependency A → B, then it is necessarily true that B → A.
21) A determinant of a functional dependency may or may not be unique in a relation.
22) A key is a combination of one or more columns that is used to identify particular rows in a
relation.
23) A row can be uniquely identified by a key.
24) A combination key is a group of attributes that uniquely identifies a row.
25) A key can be composed of a group of attributes taken together.
26) It is possible to have a relation that does not have a key.
27) A candidate key is one of a group of keys that may serve as the primary key in a relation.
28) A relation can have only one candidate key.
29) A primary key is a candidate key that has been selected to uniquely identify rows in a
relation.
30) A surrogate key is an artificial column that is added to a relation to be its primary key.
31) Surrogate keys usually slow performance.
32) Surrogate keys are normally not shown on forms or reports.
33) A foreign key is one or more columns in one relation that also is the primary key in another
table.
34) A referential integrity constraint is used to make sure the values of a foreign key match a
valid value of a primary key.
35) A constraint that requires an instance of an entity to exist in one relation before it can be
referenced in another relation is called an insertion anomaly.
36) A referential integrity constraint limits the values of a foreign key.
37) If a table meets the minimum definition of a relation, it has an effective or appropriate
structure.
38) Undesirable consequences of changing the data in a relation are called modification
anomalies.
39) A deletion anomaly exists when deleting data about one entity results in the loss of data
about another entity.
40) Relations are classified into normal forms based on the types of modification anomalies that
they are vulnerable to.
41) Any table that meets the definition of a relation is said to be in first normal form (1NF).
42) Any table that meets the definition of a relation is in 2NF.
43) A relation is in 2NF if and only if it is in 1NF, and all non-key attributes are determined by
the entire primary key.
44) A relation is in 3NF if and only if it is in 2NF, and there are no non-key attributes determined
by another non-key attribute.
45) The condition that a non-key attribute determines another non-key attribute is known as
transitive dependency.
46) An attribute is a non-key attribute when it is a non-prime attribute, which means that the
attribute is not contained in any candidate key.
47) Candidate keys are called interlocking candidate keys when they share one or more
attributes.
48) A relation is in Boyce-Codd Normal Form (BCNF) if and only if it is in 3NF and every
determinant is a candidate key.
9
49) A relation is in Boyce Codd Normal Form (BCNF) if and only if it is in 3NF and every
determinant is a candidate key.
50) Every time we break up a relation during the normalization process, we may have to create a
referential integrity constraint.
51) The essence of normalization is taking a relation that is not in BCNF and breaking it into
multiple relations such that each one is in BCNF.
52) When designing or normalizing relations, each relation should have only one theme.
53) A multivalued dependency exists when a determinant is matched to a set of values.
54) The multivalued dependency noted as A → → B, means that the value of A determines a set
of values of B.
55) A relation is in 4NF when multivalued dependencies are isolated in their own relation.
56) A relation is in 4NF if it is in BCNF and it has no multivalued dependencies.
57) Domain/key normal form requires that every constraint be a logical consequence of the
definition of domains and keys.
58) A relation that is in domain/key normal form is assured to be free from all anomalies.
59) Which of the following is not true about a relation?
A) Has rows containing data about an entity
B) Has columns containing data about attributes of the entity
C) Has cells that hold only a single value
D) Can have two identical rows
60) Which of the following is true for a relation?
A) Entities in a column vary as to kind.
B) The order of the columns is important.
C) The order of the rows is unimportant.
D) More than one column can use the same name.
61) A relation is also known as a(n) ________.
A) table
B) tuple
C) relationship
D) attribute
62) A tuple is also known as a ________.
A) table
B) relation
C) row
D) field
63) An attribute is also known as a ________.
A) table
B) relation
C) row
D) column