Chapter 3: The Relational Model and Normalization
1) All relations are tables, but not all tables are relations.
Answer: TRUE
Diff: 1 Page Ref: 120
2) A relation is a three-dimensional table.
Answer: FALSE
Diff: 2 Page Ref: 121 Fig 3-4
3) A characteristic of a relation is that the cells of the relation hold a single value.
Answer: TRUE
Diff: 1 Page Ref: 121-123 Fig 3-4
4) A characteristic of a relation is that the rows of a relation may hold identical values.
Answer: FALSE
Diff: 2 Page Ref: 121-123 Fig 3-4
5) A relation is a table composed of columns and rows.
Answer: TRUE
Diff: 1 Page Ref: 121-123 Fig 3-4
6) In relational terms as defined by E.F. Codd, a row is called a tuple.
Answer: TRUE
Diff: 1 Page Ref: 123-124 Fig 3-9
7) In relational terms as defined by E.F. Codd, a column is called an attribute.
Answer: TRUE
Diff: 1 Page Ref: 123-124 Fig 3-9
8) The columns of a relation are sometimes called tuples.
Answer: FALSE
Diff: 1 Page Ref: 123-124 Fig 3-9
9) A tuple is a group of one or more columns that uniquely identifies a row.
Answer: FALSE
Diff: 1 Page Ref: 123-124 Fig 3-9
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.
Answer: TRUE
Diff: 1 Page Ref: 124
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.
Answer: TRUE
Diff: 2 Page Ref: 124
12) In functional dependencies, the attribute whose value is known or given is referred to as the determinant.
Answer: TRUE
Diff: 2 Page Ref: 124
13) Attribute Y is functionally dependent on attribute X if the value of attribute X determines the value of Y.
Answer: TRUE
Diff: 2 Page Ref: 124-126
14) The functional dependency noted as A → B means that the value of A can be determined from the value of B.
Answer: FALSE
Diff: 1 Page Ref: 124-126
15) In the functional dependency shown as A → B, B is the determinant.
Answer: FALSE
Diff: 2 Page Ref: 124-126
16) Functional dependencies can involve groups of attributes.
Answer: TRUE
Diff: 1 Page Ref: 124-126
17) Given the functional dependency (A, B) → C, the attributes (A, B) are referred to as a composite determinant.
Answer: TRUE
Diff: 2 Page Ref: 124-126
18) Given the functional dependency A → (B, C), then it is true that A → B and A → C.
Answer: TRUE
Diff: 3 Page Ref: 124-126
19) Given the functional dependency (A, B) → C, then it is true that A → C and B → C.
Answer: FALSE
Diff: 3 Page Ref: 124-126
20) Given the functional dependency A → B, then it is necessarily true that B → A.
Answer: FALSE
Diff: 3 Page Ref: 124-126
21) A determinant of a functional dependency may or may not be unique in a relation.
Answer: TRUE
Diff: 2 Page Ref: 128-129
22) A key is a combination of one or more columns that is used to identify particular rows in a relation.
Answer: TRUE
Diff: 1 Page Ref: 129
23) A row can be uniquely identified by a key.
Answer: TRUE
Diff: 1 Page Ref: 129
24) A combination key is a group of attributes that uniquely identifies a row.
Answer: FALSE
Diff: 1 Page Ref: 129
25) A key can be composed of a group of attributes taken together.
Answer: TRUE
Diff: 1 Page Ref: 129
26) It is possible to have a relation that does not have a key.
Answer: FALSE
Diff: 3 Page Ref: 129-130
27) A candidate key is one of a group of keys that may serve as the primary key in a relation.
Answer: TRUE
Diff: 1 Page Ref: 129-130
28) A relation can have only one candidate key.
Answer: FALSE
Diff: 2 Page Ref: 129-130
29) A primary key is a candidate key that has been selected to uniquely identify rows in a relation.
Answer: TRUE
Diff: 1 Page Ref: 129-130
30) A surrogate key is an artificial column that is added to a relation to be its primary