Chapter 6

Question 1

The first step in the database design process is to create tables and columns from entities and attributes.

Answer 1

True

Question 2

When creating a relational database design from E-R diagrams, first create a relation for each relationship.

Answer 2

False

Question 3

Each entity in the extended E-R model is represented as a table in the relational database design.

Answer 3

True

Question 4

An entity needs to be examined according to normalization criteria before creating a table from it in the relational database design.

Answer 4

False

Question 5

When creating a table in the relational database design from an entity in the extended E-R model, the attributes of the entity become the rows of the table.

Answer 5

False

Question 6

By default, the identifier of the entity becomes the foreign key of the corresponding table.

Answer 6

False

Question 7

The ideal primary key is short, numeric, and fixed.

Answer 7

True

Question 8

A surrogate key is appropriate when the primary key of a table contains a lengthy text field.

Answer 8

True

Question 9

One of the important properties of an attribute is whether or not it is required.

Answer 9

True

Question 10

A surrogate key is a unique, system-supplied identifier used as the primary key of a table.

Answer 10

True

Question 11

The values of a surrogate key have no meaning to the users.

Answer 11

True

Question 12

A surrogate key should be considered when the key contains a lengthy text field.

Answer 12

True

Question 13

Whether or not an attribute is required is determined during the database modeling phase.

Answer 13

False

Question 14

A null value is an attribute value that has been set to zero.

Answer 14

False

Question 15

Data types are consistent across all DBMS products.

Answer 15

False

Question 16

A default value is the value the user enters into the row the first time the user enters data.

Answer 16

False

Question 17

A data constraint is a limitation on data values.

Answer 17

True

Question 18

The last step in creating a table is to verify table normalization.

Answer 18

True

Question 19

One of the important properties of a column is whether or not it can have a NULL value.

Answer 19

True

Question 20

A foreign key is a key that does not belong in any table.

Answer 20

False

Question 21

In a relational database design, all relationships are expressed by creating a foreign key.

Answer 21

True

Question 22

When the key of one table is placed into a second table to represent a relationship, the key is called a “relational key” in the second table.

Answer 22

False

Question 23

To represent a 1:1 binary relationship in a relational database design, the key of one table is placed into the second table.

Answer 23

True

Question 24

When placing a foreign key for a 1:1 relationship, the key of either table can be used as the foreign key in the other table.

Answer 24

True

Question 25

In a 1:1 relationship, the foreign key is defined as an alternate key to make the DBMS enforce uniqueness.

Answer 25

True

Question 26

In a 1:N relationship, the term "parent" refers to the table on the "many" side of the relationship.

Answer 26

False

Question 27

In 1:N relationships, the table on the "one" side is called the parent.

Answer 27

True

Question 28

In representing a 1:N relationship in a relational database design, the key of the table representing the parent entity is placed as a foreign key in the table representing the child entity.

Answer 28

True

Question 29

In representing a 1:N relationship in a relational database design, the key of the table representing the entity on the "many" side is placed as a foreign key in the table representing the entity on the "one" side of the relationship.

Answer 29

False

Question 30

To represent a 1:N relationship in a relational database design, an intersection table is created.

Answer 30

False

Question 31

In 1:N relationships, the table on the "many" side is called the child.

Answer 31

True

Question 32

To represent a one-to-many relationship in a relational database design, the key of the child table is placed as a foreign key into the other table.

Answer 32

False

Question 33

To represent an M:N relationship in a relational database design, a table is created to represent the relationship itself.

Answer 33

True

Question 34

To represent an M:N relationship in a relational database design, an intersection table is created.

Answer 34

True

Question 35

To represent an M:N relationship in a relational database design, in essence it is reduced to two 1:N relationships.

Answer 35

True

Question 36

The key of an intersection table is always the combination of the keys of both parents.

Answer 36

True

Question 37

In many-to-many relationships in a relational database design, the primary keys of both tables are joined into a composite primary key in the intersection table.

Answer 37

True

Question 38

An intersection table is always ID-dependent on both of its parent tables.

Answer 38

True

Question 39

An intersection table can have additional attributes besides the keys of its parent tables.

Answer 39

False

Question 40

Like all ID-dependent relationships, the parents of an association table are required.

Answer 40

True

Question 41

Association tables sometimes connect more than two entities.

Answer 41

True

Question 42

An ID-dependent table can be used to represent multivalued attributes.

Answer 42

True

Question 43

All identifying relationships are 1:N.

Answer 43

True

Question 44

When creating a table for an ID-dependent entity, both the key of the parent and the key of the entity itself must appear in the table.

Answer 44

True

Question 45

The design transformation for all IS-A relationships can be summarized by the phrase "place the key of the parent table in the child table."

Answer 45

False

Question 46

When transforming an ID-dependent E-R data model relationship into a relational database design where the child entity is designed to use a surrogate key, the relationship changes to a weak but not ID-dependent relationship.

Answer 46

True

Question 47

When transforming supertype/subtype entities into a relational database design, an entity is created for the supertype only.

Answer 47

False

Question 48

When transforming supertype/subtype entities into a relational database design, the key of the supertype table is placed into the subtype table typically as the key.

Answer 48

True

Question 49

To represent an IS-A relationship in a relational database design, the IS-A relationship must be converted into a HAS-A relationship.

Answer 49

False

Question 50

Discriminator attributes can be represented in relational designs.

Answer 50

False

Question 51

When transforming supertype/subtype entities into a relational database design, all of the attributes for the supertype table are placed into the subtype relations.

Answer 51

False

Question 52

When transforming an extended E-R model into a relational database design, recursive relationships are treated fundamentally the same as other HAS-A relationships.

Answer 52

True

Question 53

Recursive M:N relationships are represented with an intersection table that shows pairs of related rows from a single table.

Answer 53

True

Question 54

Referential integrity constraints should disallow adding a new row to a child table when the foreign key does not match a primary key value in the parent table.

Answer 54

True

Question 55

A referential integrity constraint policy that insures that foreign key values in a table are correctly maintained when there is a change to the primary key value in the parent table is called cascading changes.

Answer 55

False

Question 56

A referential integrity constraint policy that insures that all rows containing a particular foreign key value in a table are eliminated from the table when the row containing the corresponding primary key value in a parent table is eliminated from the database is called cascading deletes.

Answer 56

True

Question 57

When the parent entity is required (M) in a relationship, every row of the child table must have a valid, non-null value of the foreign key.

Answer 57

True

Question 58

Cascading deletions are generally not used with relationships between strong entities.

Answer 58

True

Question 59

Cascading deletions are generally not used with relationships for weak child entities.

Answer 59

False

Question 60

If the parent is required, then a new child row must be created with a valid foreign key value.

Answer 60

True

Question 61

When the parent entity has a surrogate key, the enforcement actions are the same for both parent and child.

Answer 61

True

Question 62

When the child entity is required (M) in a relationship, there needs to be at least one child row for each parent row at all times.

Answer 62

True

Question 63

It is easy to enforce the referential integrity actions for M-M relationships.

Answer 63

False